Passkeys are stored in your password manager, too. You'll only lose access to your passkeys if Google is your password manager and you get locked out of your Google account. So, if you don't trust Google, use another password manager. (May I recommend Bitwarden?)
The advantage of passkeys is that no one can trick you into giving your passkeys to the wrong person. Every time this comes up, people say "I don't need that! I've got a password manager. I'm too smart to get tricked." But they are wrong.
The advantage of passkeys is that no one can trick you into giving your passkeys to the wrong person. Every time this comes up, people say "I don't need that! I've got a password manager. I'm too smart to get tricked." But they are wrong.