Halo MCC STEAM VER not launching


Since I installed halo 1 mp (but not the campaign) the game won’t launch through steam.
I tried verifying files through steam, did nothing.

I get the box: play halo the mcc then it loads and then nothing.

I tried to submit a support request but really, this system…
Gamertag, game mode, game map, is required to ask a question, I can’t launch the game so gg with that.

If I try to google this, I only find issues with gamerpass, not with steam.
Any help please? Thanks, only thing I can think of is reinstalling the whole thing but i’d rather not atm.