AFAK if a conflict occure, it will create a "conflicted copy" of the kdbx file. You still have to merge files manually but no data will be lost in the process.

I concur with the other commenters... I've been syncing with dropbox for years now and never had a conflict. I guess it helps I tend not to leave it open/running on multiple machines. Open it, use it, close it.

> At the very least, a .kdbx on Syncthing/Droxbox-like storage WILL eventually lead to data loss.

It's been working for me without issue since 2009-ish. I've used 1.x and 2.x databases in Dropbox.

At some point new passwords will be added quite rarely. Clash can happen, but in practice I've been happily using this method now for years and years.

Keepass will let you merge the databases if a conflict happens.