So time passed by, theres no word from 343, no word from EasyAnticheat or EpicGames and in the mean time i reinstalled my entire operating system.
It turns out, that EasyAntiCheat simply does not support Windows 7 anymore and causes the crash.
I can not explain it in any other way this must be the only reason why its always crashing at the startup.
Its also definitely due to easyanticheat, as, again, the game launches perfectly fine in the "easyanticheat disabled" mode, but then i cant play multiplayer, which is like the main reason i bought mcc in the first place
So yeah RIP