lowdude

Things like FiveM exist, which is exactly that. I’m not sure if that is at all affected by the anticheat though, I didn’t read the article.

There are many ways to contribute. I actually read an article about that a couple of days ago, maybe it will be of interest to you, too: https://github.com/readme/featured/open-source-non-code-contributions

This is a rather specific question, but can you cast audio from arbitrary apps to WiFi speakers from your Pixel? Similar to airplay on iOS (if that's what it is called)?

That's exactly what it is. I haven't looked into it too much, but as far as I know it's main advantage is simplifying the setup process, which in turn reduces the chances of a misconfigured VPN.