I see. For this scenario, I have another Syncthing server, which is on 24/7, responsible for offsite backups.

Ad encrypted files: true, but why expose them to a potential adversary? If there should be a flaw in the encryption (now or future) the other party already has access to the file.

Why would you do that? Just sync thr database with Syncthing and keep it locally on your devices. I’d never put my pw dB in a publicly available cloud online, even though it’s encrypted.