I'm logging into websites using unique passwords with 44 bits of entropy, which they feed into a hash algorithm that takes 200ms to hash each attempt, then entering a TOTP code or touching my Yubikey, and they check against my geoip history and fingerprint my browser and they want me to complete a captcha and they e-mail/SMS a one-time code to me and they send me an e-mail telling me there's a new login to my account.

The security industry loves to use belt and belt and braces and braces and braces. If they add an extra belt or two, I doubt anyone will remark on it at all.

The two key issues PQC try to address are key exchange and digital signature, which happen during TLS handshake, the mechanism you described happen after TLS is established; so if a quantum computer breaks TLS, then it effectively reduced HTTPS to HTTP

The amount of time I spend per day waiting for my web browser to do about 10 redirects through Okta and touch a Yubikey is substantial.