More and more, I think the best replacement for a cloud drive is just Syncthing.
I went through the list and wrote what I use to replace it.
Microsoft Office 365
-- Mail -> Tuta
-- Calendar -> I don't use a calendar, but Tuta would be my option
-- OneDrive -> I still use OneDrive, but I'm also using Filen.io and Syncthing
-- Documents* -> ONLYOFFICE (Documents)
Bitwarden -> KeePassXC and Keepass2Android
GitHub -> I still use GitHub...
Google search -> SearXNG with several search engines
*Documents weren't listed or mentioned since they're not cloud services, but I think it's worth talking about. I'm just using ONLYOFFICE and syncing everything with Filen.io and Syncthing.
I didn't realize until this thread because the only instance I had looked at was https://cryptpad.disroot.org/ , which doesn't seem to have updated to the OnlyOffice version of CryptPad.
Convenience, I suppose. It's not like Syncthing is hard to setup, but it is harder than the centralized stuff, namely because there's talk of relay and discovery servers... That doesn't really "matter" for a regular user, but normies see funny words and give up.