Are there people playing AI + human vs AI + human games? I think it might be fun to play an RTS against someone where the only rules are no hacking the game itself, but writing harness, macros, any kind of stack is allowed.
https://olamarena.com/ is sort of this but not with full code manipulation like you describe
there is screeps, but afaik it's purely scripted with no "live" human playing
Codingame.com has a few fun arenas.