I just can’t take an article complaining about ads seriously when it’s that peppered with ads …

Only if it’s installed somewhere beneath the current working directory, whichever that might be when running the command.

The answer to every single one of those questions is: Conan the Barbarian

I like my stuff self-managed.

Bitwarden / Vaultwarden is a popular available working solution for self-hosting and self-managing passkeys (as well as passwords).