Comment by noobgrammer

EDIT: Cloudflare already made a game demo on Workers... multiplayer Doom: https://blog.cloudflare.com/doom-multiplayer-workers/ that was written using WASM + WebSockets, porting over an open-source Doom and shimming in a UDP-over-Websockets networking layer. Despite all that, it's still fast enough for a first person shooter.

Original post: Have you looked into using a serverless pub/sub model, like Cloudflare's Workers KV? The example they give is a simple IRC-like distributed chatroom (https://github.com/cloudflare/workers-chat-demo), but theoretically it may work for games too.

Player state can be stored in a decentralized key-value store that Cloudflare manages (Cloudflare Durable Objects). They absorb all the DDoS and handle replication between edge nodes. You don't see any of that. https://developers.cloudflare.com/workers/learning/using-dur...

Then each game client uses a worker to access that KV on a subscription basis, and Cloudflare will route that worker to its nearest edge node and retrieve the state from there (which was previously replicated a moment ago, internal to Cloudflare's infrastructure). Changes to state are replicated across the edge network and pushed to client workers.

https://workers.cloudflare.com/

I don't know if this would result in acceptable latency, but it could help with DDOS at least. The main benefit is that it's incredibly affordable, especially when you're only talking about thousands of players.