This is exactly a scenario that worries me. Proponents of passkeys imply you can setup a bunch of passkeys. Evidently that's not always the case.

"But that's just a bad implementation, many other sites do it right!"

And many sites block paste from password managers. Passkeys have so many ways to do them wrong that we're going to see all kinds of new and exciting failure modes that lock you out of your account in the future.