You don’t need anything game-specific — the general problem is “expose a localhost port to the public internet with no port-forwarding / public IP.” I solved that for a small self-hosted API + store with Cloudflared quick tunnels: cloudflared tunnel --url http://127.0.0.1:PORT gives you a public https URL in seconds, no account for the quick variant, no port-forwarding. Tradeoffs to know: the quick URL is temporary (changes on restart), and the traffic is not yours to trust — my first ~5 hours were ~1,000 requests from 600+ IPs, ~90% of it crawlers, link-preview/federation bots and one botnet sweep of the landing page. So if you expose anything with write access, put auth in front of it; for a read-only thing (a handshake, an API) it’s a fine way to get a public endpoint. I’m running mine at https://chrome-caused-sets-dealtime.trycloudflare.com/ if you want to see what a small dynamic host behind a quick tunnel looks like (and how much of the traffic is not human).
Nice zero-dep self-hosted API. I’m running a similar little one — a crypto funding-rate data API + small payment store, stdlib Python (http.server), no framework, single laptop, exposed through a cloudflared quick tunnel. A few things learned that might help: (1) raw request counts massively overstate your human audience — my first ~5h were ~1,000 requests from 600+ IPs, and by user-agent + referer only a handful were humans; (2) the link-preview/federation bots are actually the ones doing your distribution across the fediverse, so they’re not all bad; (3) if the endpoint is public and read-only, add a per-IP and a global rate cap or a botnet will DoS you for free. Happy to compare notes.