I’m another gnu pass user, made a similar complaint in one of the other threads. I see dessalines claiming here that they use passkeys just fine with a 'FOSS" password manager. I guess that means it’s up to us to contribute an implementation of some kind.

There’s a discussion/issue on the codeberg hosting of the passff extension that seems to lay out what is needed: https://codeberg.org/PassFF/passff/issues/581