Your connection isn't private on edge after hardening plus no home page

“ERR_CERT_NO_REVOCATION_MECHANISM” means the certificate has no revocation mechanism, I.e., no CRL or OCSP reference.
I can imagine some CAs issue short-lived certificates and thus provide no means to revoke them. Letsencrypt would be an obvious example, but they *do* provide revocation means via OCSP.
Google, too, issues short-lived (3 months long) certificates for www.google.com but they, too, provide OCSP and CRL in their certificates, at least, for me.

Could it be you are using some middle box (e.g., PaloAlto Networks or Cisco firewall) on your network or antivirus on your computer that does https interception and substitutes certificate with their own? To confirm that, can you view the certificate you get and check if it’s really Google’s? Google certificate is issued by GTS CA which is issued by GTS Root R1. You can inspect real certificates via https://www.ssllabs.com/ssltest/