The real solution is to limit information sent to the client, make it harder for cheaters to have reliable solutions to get access to critical game information. ARC Raiders has Theia anti tamper (very poor performance) but right now the number of cheaters is minimal because the select few who are smart enough to break the anti-tamper are keeping quiet. See other examples; The Finals, Roblox (Byfron) and Overwatch
Yeah, I mean why would they open source their anti-cheats, would defeat the purpose, wouldn't it?
Not sure why you bring up OSS here, it isn't relevant in the least, plenty of non-OSS runs on Linux even though Linux and more is OSS.
If Linux did the same, anyone could recompile the kernel with their fake anticheat’s signature. The fake anticheat would then present itself as real to the game. One could go as far as to rewrite the relevant syscall to falsely indicate to the game that the legitimate version is running.