Yes, if your threat model is "what if Google locks me out?" Then you won't want to rely on a Google passkey as your only way of logging into a website.

Ideally, websites will support multiple passkeys per account. I think having both Google and Apple passkeys would be sufficient since I think I would be unlikely to be locked out of both.

Apparently Tailscale doesn't have multiple passkeys per account, but they recommend creating a backup admin account, and you could use a different kind of passkey for it.