Your proposed solution isn't a very good one. Actual password systems use server-side things like salts and other mechanisms like hashing. Having "trivial" clie

Your proposed solution isn't a very good one. Actual password systems use server-side things like salts and other mechanisms like hashing. Having "trivial" client-side extension to generate a certificate would make brute-force a lot easier. So, if passkeys are the only way of logging in, then no, a browser-based certificate generator would not work to emulate passwords.