SO apparently the mcu is designated as Earth-19999 which I guess means it was a part of the marvel multiverse which was destroyed in the Secret Wars event.

Which then lead to Franklin creating the universes and Reed using the Beyonders power physically willing them into existence. The mcu if a part of the marvel multiverse would've been one of these meaning Reed and Franklin created it

So the mcu was destroyed and then re-created and nobody knows

I doubt anyone at marvel will ever acknowledge this but still cool either way ahaha