If you want wife acceptance factor put opnsense on stand alone hardware and religiously backup the config. Sucks losing network when your virtual machine host needs rebooting
Even my current stand alone firewall occasionally needs to reboot when I upgrade the SW. I purchased a Qotom that is a beast for the bucks with 10 ports and enough resources to run many other server apps. I expect to only restart VM's when needed rather than the whole box. I am religious about backups with a 3/2/1 strategy that includes a RPI in the shed within WIFI range for nightly backups.
Proxmox gets regular updates thatoften request reboots. It serms at abhigher rate than my opnsense box. Unless you are doing a high availability setup and live migrating it to another nodr, that means additional downtime