How do you back up and restore things without root? I've found that even with root, these days many backups are useless thanks to using hardware-backed encryption...
I don't. I transfer any important data like photos to a real computer weekly
Mail, Calendar and Contacts are handled by IMAP and DavX. Passwords are in 1Password
I have minimal apps so setting up a new device wouldn't be too much trouble
That's not true though, is it? "Everything" kind of implies an iPhone-style backup. You can't do that without root AIUI
Maybe you can give us more details about how you achieve a full up-and-running restore "in minutes"? I run GrapheneOS so very interested.
(Syncthing for Android is deprecated, too)