I can only speak for myself, but I would never trust opaque, proprietary software to manage my credentials, especially in a networked environment. For me, that's a total showstopper.
I've never had need to use Bitwarden or Vaultwarden as I've always been happy with KeePass, but this news would definitely have me choosing an alternative.
For what it's worth, I only ever had sync issues when sharing a database between devices with transient connectivity. Once I added an always-on instance of Syncthing into the mix, collisions were a thing of the past.
We've been using KeePass trouble-free for many years now, sharing a single database across more than 6 devices, with frequent use and modification.
Noooo! Ugh, that's so disheartening to hear but I can't fault imsodin for his reasons. I sincerely hope that someone steps up to the plate, even if only for the F-Droid releases.
For anyone else interested, the discussion is taking place here:
https://forum.syncthing.net/t/discontinuing-syncthing-android/23002/7