Right now on Firefox for Android (I use it on macOS, Windows, Linux, and iOS without issue) I’m only able to sign into websites requiring passkeys with my on-device or Google account passkeys. I can’t sign in using my 1Password passkeys like I do on all the other platforms. There was a bug fix I was watching the status of (got fixed a few weeks or a month ago) that should be included in the next Firefox release (128), fixing this annoying issue :-)
Firefox 127 Released with Improved Screenshot Tool, Security Boost (www.omgubuntu.co.uk)