Syncthing also has untrusted hosts support now: you can sync your files to a host you don't trust, and it keeps them encrypted on the destination.

Very cool. Looks like it's currently marked beta/testing.

The main issue is you can accidentally nuke your own source directory and it's possible to do so in non-obvious ways. This has happened to me a few times (though thankfully had backups elsewhere).

SyncThing comes with a built-in feature to keep the last n versions of files around[1], for added peace of mind.

https://docs.syncthing.net/users/versioning.html

It only works though if you dedicate a separate server for sync.