totally anecdotal.... but i've installed debian on a bunch of different machines and i've never had to "prepare additional installation media" for any weird hardware/firmware/drivers.... i just installed the base system and connected ethernet if any non-free stuff is needed. has anyone ever come across an ethernet interface that didn't work out of the box? maybe it didn't work 100%, but at least good enough to download the proper firmware to fix?
Well, my laptop doesn't have an ethernet port. When it happened to me (not on Debian, I think Mint or something), I didn't even use a phone OS that was capable of sharing my internet via USB. Fun times.
Thats why i said you just need a few minutes on ethernet.... Although i can see the problem these days with a lot of laptops shipping without ethernet ports