You could use PiVPN (you don’t need to install it specifically on a Raspberry Pi – this is just a handy all-in-one software solution). It supports both OpenVPN and Wireguard standards. Forward the relevant port in your router configuration, set up a single user for yourself in the VPN settings, and then connect via whichever client you prefer (OpenVPN if you use OVPN, or Wireguard if you use Wireguard).
I’ve used it before to access locally-hosted services from outside my home network and it gets the job done with fairly minimal setup.
Could try hosting a Multi-User Dungeon (MUD). I tried to host an Evennia server last year but could never get it to work properly. Wasn’t a big deal though cause it’s not like I had any friends who wanted to play, lol.