I like proxmox, but it kinda sounds like you’d be just fine with just docker running on opensuse or debian. Or whichever the favorite container is these days (idk why podman is so great, but I seent some posts about people that love it.)
I have tiered out my server with all my app services (jellyfin, nextcloud, etc) running in docker on a debian vm, then have lxc containers for nfs, VPN, etc. Proxmox itself handles ZFS, but I’m sure that’s bad practice and there is probably a better way - but it works for me so 🤷.
I’ve also got a opnsense vm, but not used for any “production” atm; just checking it out to see if I should switch my pfsense box over.