DeletedUser720 If you already have passkey on your key, use Firefox, it looks like atm that's the only browser that works. Vanadium stopped to work for me some time afo.
Vanadium works for me. I haven't seen other reports of regressions in Vanadium regarding FIDO. More details about your setup would be needed to assist you with this.
DeletedUser720 You may also need to:
use isolated play services (don't give it network permissions and disable it once done) - it's not a big deal read the GOS guide if you're hesitant
select Google as autofill in Android Settings
This is definitely not related to getting security keys working with Play services. Play services actually needs to contact the internet the first time you authenticate with a security key.