The maker of the credential manager is still a "big tech company", and there is still lock-in. Before I ever use any passkey solution, I would need to be guaranteed the ability to export and backup my passkeys and migrate them wherever I want.

My expectations for how long I intend to be alive and using the internet is much longer than my expectations for the continued operation and service of any particular passkey management software.

I already had to jump ship from LastPass after they were hacked. Imagine if they hadn't allowed me to migrate my passwords.

Bitwarden is a great option for you. You can even self host it!