I use keepassxc on MacOS, Windows, Linux, along with MiniKeePass on iOS. It's synced through my free Dropbox account. I just make sure to set the preferences so that every change to the key database results in a file save.
I use syncthing for some backups, no idea why I've never considered it for keepass. Probably cause I don't want to mix the two and clients don't offer it already integrated. Or are there any? It for sure wouldn't make building the project more easy, and the password manager is the one thing i still want to build form source to at least imagine I have full control over it.
I use keepassx and yeah it could use some tlc, but overall I consider stability a feature in security software. How does one tell if xc isn't just a bunch of wannabes making keepassx with blackjack and hookers until they break it? At least keepassx has taviso's off-handed Twitter comment that it "looks sane".