Fourth amendment protects against unreasonable search and seizure. That applies to passkeys. First amendment protects speech, that’s what protects your password. You can’t be compelled to tell that because you can’t be compelled to say things, not because there’s any protection against the data being seized. IANAL, feel free to go into more detail if you still disagree

Passwords are protected (for now) by the first amendment. You can’t be compelled to tell what it is. Passkeys can be seized with a warrant. This only matters in the US but it does matter and I literally never see that addressed.