If you’d like to run them on the same Ubuntu VM, I’d recommend deploying them using docker, as that will make avoiding port conflicts much easier as well as keeping each application isolated.
You should also look into a reverse proxy so you can reroute traffic from your desired subdomain to non-standard ports (otherwise you’ll need to specify ports in the URL which gets weird). I recommend Nginx Proxy Manager which can also run in docker.
You could spin up another VM for Lemmy if resources get tight and you don’t mind the extra cost.
INTERGALACTIC: THE HERETIC PROPHET, a new Naughty Dog game in the works looks like it might be Cyberpunk themed. It’s SciFi at least.