For my mom the year of the Linux desktop it's already over

How is /etc/fstab configured? Partitions should be assigned to mount points by UUID and not by their names (such as /dev/sda1). Names can easily change across boots.
Something to look into. Understand the frustrations here, but it looks like something that can be fixed if you are able to get to the machine and troubleshoot.

If the EFI partition truly was at fault, you wouldn’t get into Linux. And if the issue is mounting the efi partition after booting, that shouldn’t be a critical error. So it sounds like something else is at fault IMO

What distro did this happen on?
How long ago did you install it?
- Pop os, a few months ago
  
  Try silverblue or kinoite something immutable that will not break
  
  Pop os wasn't the best distribution to start her on. It's new. Unstable and updates often. Linux mint, Debian, fedora.
  
  wild
  I've been off and on popos for like a 5 years and other than early issues with sound and Bluetooth, don't ever even think about
  
  Are updates being done by the OS automatically or are you going into the terminal and running an apt-get upgrade periodically?
  I've had issues when I do a terminal update because I believe that Pop expects you to do an apt-get dist-upgrade

That happens when I select the wrong kernel in the systemd boot menu, before that screen. Doing nothing after an upgrade also selects the wrong version by default, it's kinda annoying. I have to select the most up to date version and press Ctrl-D to make it the default on the next boot.
If that's also what happens here, maybe a solution could be to keep only one kernel version and its fallback. But idk if you're using systemd-boot or grub
- You might try using rEFInd instead.

I switched my Dad to Linux recently, and set his account up without any superuser access. Updates have to wait until I visit once a week, but it restricts his ability to get himself stuck in any update-related tangles.
Linux has problems, but I'm so glad I don't have to support my Dad on Windows anymore, because that was far less predictable for me. Like the time it decided to upload all his files to onedrive (despite him having no knolwledge of this, or what it was doing or whether he'd consented or not) and made the Internet unusably slow for 8 hours by totally saturating his meagre connection.
He didn't even know about onedrive, just phoned me like "The Internet isn't working, what's wrong?" and of course onedrive is the last thing I'd have suspected for causing that symptom, which made it so annoying to diagnose.
Much nicer now his OS doesn't do sneaky things behind his back, or mine.
- I had a colleague at work that had to redo several days of work because of the one drive thing.
  The long and short of it is that they noticed that their connection was being super slow, opened up task manager to see if anything was eating bandwidth, saw one drive, went it it, correctly diagnosed that it was uploading files to it and eating up bandwidth, and then deleted all the files in one drive to stop it.
  One drive decided that this meant they wanted all the local copies of the files deleted as well. Like, on the one hand, not the correct way to stop that behavior, but also like, the kind of thing a lot of people would try, and it then deleting all the local files in turn is an unintuitive outcome.
  
  Yeah. When the cloud has more control over your own files than you do, that's not a feature, it's a problem.
  
  Google Photos pulled the same shit after it uploaded all of the my photos on my phone without permission. Eventually I tried to delete a bunch of pictures off the app, with the trashcan button... and soon realized that they were being erased from my actual phone storage as well. No warning, or indication that it would do so. Like wtf
- set his account up without any superuser access
  Oh, revenge for when he had parental restrictions on the router and you couldn't get to teh pron, huh?
  I like it.
  
  Hehe, you might think that!
  In actuality though, I've always been the one who had to sort the tech stuff. We got our first family PC when I was 10, and I was the one who knew the most about it. We got the Internet when I was 13, and I was the one who had the passwords, and had to set it all up. Then when we got broadband, the router was actually in my room lol.
  So yeah, I've always been the Admin, and Dad has always been the one who needed a limited account to protect him from himself.

Loool, all the people who are trying to help you troubleshoot are 1) probably correct and 2) completely missing the point. I have a Windows desktop, a Mac, and a Linux desktop at home and this kind of shit only happens on Linux these days.
- How am I the only one who does have annoying issues like this on Windows (except that Windows only gives a useless error code at most) while Linux has failed to boot a total of once (without me explicitly changing nvidia drivers).
  
  System breaking errors that doesn't allow you to even login?
  Windows have lots of issues, but it's been a while since I found those system breaking issues to be somehow common.
  For all their shit, credit myst be given when credit is due. And windows it's become a really robust systems against layer 8 issues. Even powering off middle update is kind of easy to recover (I have to solve this issue for a user recently).
- Literally happened updating just yesterday so I went to an older boot entry. The Matrix channel blamed my hardware, but the older revision boots just fine
- You're right, this never happens on windows. It's so robust no one ever complains
  /s
- My MacBook is getting very long in the tooth and the updates via OCLP are working in creating a system that is painfully slow to use. I’ve been tinkering with various Linux distros for 20 years and the thought of having one as my only daily driver does not sound appealing. I really don’t want to drop the money on a new laptop but I need something to work without constantly troubleshooting.

RIP, this is sad day today

Great example of why a safety net is required.
Yes hopefully the "base" setup works once you installed it, hopefully manage through some updates, some even tinkerings... but what happens when it break?
Windows (despite all the criticism, and I'm one of the first to complain about Microsoft the corporation) usually has been fallback mechanisms. It can usually rollback an update. It usually has a hidden recovery partition. It usually has an alternative medium to recover (e.g. USB stick, CD-ROM back in the days, etc).
So... you genuinely did try to help your mother but do not give up. Try instead to provide a better safety net so that she is genuinely safer. In fact I would recommend testing it together, make it a learning adventure. One way to do so would be to go there, help her fix it... then botcher the setup together! Delete system files, etc, then try again. Obviously the 1st step is insuring her own data (e.g. family photo, documents, etc) is safe.
While doing so, you might also want to setup up remote control, or not. Anyway a LOT of things to genuinely discover together.
IMHO if you do do it, she will not only appreciate the effort but assuming you do manage, she'll have a new sense of pride, both in you but also herself and share the experience with her friends. This in turn might bring more people in!
- There also are distros with some kind of similar safety net. Immutable distros usually let you Boot previous versions if an update breaks something. This usually means that they need a lot of storage tho. https://itsfoss.com/immutable-linux-distros/
  
  I have had to do this with fedora in the past and i was able to fix my boot issues and then go back to the newest version

Really out of my depth here, but anyway—
What model computer does your mom have? Does it by any chance have solid state drives that are RAID 0?
Have you tried Linux Mint? After really struggling with Fedora, I was able to get Mint up and running after a few minimal problems and haven't looked back since.

It's good your mom tried. It's sad she gave up so soon. I've helped 4 people switch in the past months. I've gotten even more people curious and more open to switch. A success is not only the switch, but that people start to realize that they can. In my opinion. :-)

I gave my dad one of my spare laptops four years ago; it had never had Windows on it (being from the halcyon days when Dell sold laptops with linux pre-installed), so I put Mint on it for him.
Early this year he called and said one of the keys stopped working so he'd bought a newer, used laptop and could I help him put Linux on it, because that's what he was used to. Over the phone, I helped him download and burn a new Mint image from his ancient desktop, and verbally walked him through switching the bios to boot from the USB, and through the Mint install menus.
Since then, he's called me once for technical support for getting his printer connected.
Dad's in his 80's and was a cop with an associate's degree; he's never claimed to be a brainiac. That is what convinced me Linux is ready for anyone, but that the choice of distribution is important. I think dad never upgrades or installs new software, but that's OK. I have to update and reboot every week because I'm stupidly loyal to Arch.
I'm sorry that your mom had a bad experience; that's super frustrating.

At least your mom was cool enough to try. I had to trick my mom into using linux by putting a macOS themed, KDE, debian on an old macbook that was identical to her dead macbook

Sounds like a hardware issue, so ...
- This is every kernel update for me on Fedora. For some reason root is not set.
  
  Yours will copy a record in your grub config, for every kernel install, because that's the easiest way to get your ancillary settings. If it's happening truly every time, then I'll bet that's borked somehow.
  I ran into this because grub config now needs an additional magical parameter no one mentions, because it manages new bits to create the parts it needs with your old setup to solve no real problem. It could also be keeping a bad root statement and perennially dropping it into every new boot config. Yay! I don't remember what it was and I'm not at work, but I'll try to check later and see if I can offer some help.
- Seems like only the EFI partition is missing. She told me "ls /home/her name" shows stuff but "ls /boot/efi" is empty
  Apparently this happened by itself
  I should have chosen something like silverblue but I wasn't familiar with that
  
  How does it even get into emergency mode without the efi partition?
  
  Bluefin or Bazzite are very streamlined and easy to set up, with all the batteries included. The little you need to learn is more than offset by the convenience.
  
  Its not so easy for a user to screw-up that partition. Same things that would do it in Linux would do it in Windows.

I changed my grandad onto GNU after I've distrohopped a few times on my system just so I knew how to do a system install (which is a skill in of itself no matter what OS you are installing)
All the major technical issues for install like getting to boot, display driver issues, etc are solved. Even Nvidia is reccomending people use their open source kernel modules (nvidia-open)
That was likely some kind of kdump error, interested to know what distro you used, I often advise people to use a stable but stale distro like a Debian based distro: Mint or Ubuntu is ideal for stability and ease of install.
I setup my grandad on Mint 2 years ago,was fine but decided to hop to Archlinux KDE Plasma as needed some newer stuff(if you enable the incremental backups its not hard to switch if you think a different one is a better fit), even though Archlinux has a reputation for less stability it's been pretty good the last year, avoided AUR *mostly for stability, pamac for GUI updater.
Most of what he needs is in the browser and printing. (Printer issues are OS agnostic nowadays as modern printers seem to be very anti-consumer and they mostly use software to make their money, I.E DRM on ink cartridges)
Only issues my grandad had are printer or website related.
(Detail: used the CLI installer)
(DISCLAIMER: I am a qualified computing professional who have used GNU/Linux as daily driver since 2016, for newcomers a Debian based distro would be more the route I would).
- Archlinux KDE Plasma

Out of curiosity what did you install ? And what did you install it on ?