For the record. I'm not SOLD on passkeys as the solution but there's a lot more right with it than wrong. And passwords are just far too easy for people to screw up. There have been other attempts to replace them in the past and who knows if passkeys will catch on.
There's a spec for import and export and a 1Password blog post about it
If that solves vendor lock-in, then I'm just worried about possible attestation stuff