UPDATE: also gotta keep track separatelt of non-resident passkeys tied to Yubikey, because Yubikey doesn't know where it was used for non-resident. If you lose one yubikey, need to sync all passkeys to a new replacement one.
Though I think there is also the option that sites can store some sort of identifier on the key, then this would not work:/
That seems somewhat unrealistic? There are many passwords you need to use as part of dev work.