Pfsense is a lot more feature rich than openWRT, especially when it comes to firewall features. Personally I just use openwrt to run my access points.

I would replace that eero unit with an old dell optiplex with pfsense, and forego trying to virtualize PFSense.

Not sure what hardware is in that eero, but if you wanted to keep it as just a basic AP, that isn't a bad plan.

After that get a second optiplex for publicly hosted stuff. Keep that on a separate port on your PFSense machine, completely firewalled off from the rest of your network via pfsense, only allowing traffic from LAN to your server.

Physically separating your internal network, and publicly hosted services, as much as possible is the goal.

If you can only afford one new piece of hardware, I'd get the pfsense box, and set it up as a wireguard VPN server, disabling the direct port forwards to the VM running Minecraft. Though your friends would need to install a VPN client, and youd have to provide config files.

A used optiplex on eBay usually isn't much more money to get up and running than most Linux SoC's after all the adapters and kit is purchased, and they're usually specced out way better.

Actually if you wanted to do physical DMZ separation, and wireguard you'd really be doing good, but that's probably a little paranoid.