I have one dedicated for opnsense, which runs my firewall/router. I used to use a Ubiquiti ER-Lite, but its compute power was a little lacking for certain features I wanted running. One of the niceties of running pfsense/opnsense on a "real" computer is that it just runs faster and boots faster after a software update, haha. I also have tailscale on it so that I can remotely access my home network.
Opnsense can technically be run as a VM on proxmox, but it's generally not advised to do so. The proxmox machine is running unifi network for my ubiquiti wireless AP, adguard home, home assistant OS in a VM, and frigate in a VM, but I've been thinking of consolidating the various container services and VMs into just all containers running on a uCore OS installation instead of proxmox.