[longsword]

There will always be 0 days out there, but they will always be very expensive and rare. If you have the ressources to buy or find a 0-day, you definetly won't blow it by executing known malware, or other stuff, which falls under the detected by AV's. I really don't thing that having AV installed will protect any user from a 0-day.

On the other side, you install a very invasive av software, which runs as privileged user and intercepts everything thats happening on your system. They even make a great target for malware by themself. Just recently ClamAV had a bug in it's file scanner, which let to an rce: CVE-2023-20032