Oh, great idea! Maybe consider building it with Orbiter Simulator?

https://en.wikipedia.org/wiki/Orbiter_(simulator)

https://www.orbiter-forum.com/

https://github.com/orbitersim/orbiter

I believe it supports C and Lua.

I played Orbiter near its release - this is quite far from my intention with its focus on spacecraft and generally a low detail level.

My intention would be a game simulating, at least on a surface level, life inside an O'Neill cylinder, you being an individual doing things there that requires you to move around from the edge of the "world" to another continously, like delivering packages and such.