There are various options, but if you use syncthing, it is as easy as creating a share on your PC or backup machine and on the phone. Everything gets synced automatically.
Well everything you chose to sync gets synced. Like photos, documents etc. You can also set up apps in such a way where they make automatic local backups on your phone in the folder that gets synced. There are multiple android apps for syncthing
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)