Have you seen rumors of AMD MCM gpus where it isn't just 2 gpu dies next to each other? If so, please post the link and educate me.
If that is all that they are doing then it is driver and/or game directed MCM aka CFX.
I've used that, you probably have as well, and it isn't the same as cpu driven MCM compute, or the hardware driven, game agnostic MCM you are hoping AMD will implement while going only by rumors of the rebirth of CFX. AMD mgpu is likely for compute. In 2022 CFX sucks.
This Intel patent is detailing a vague, yet likely viable approach to that MCM you are hoping for. Hopefully one of the three builds it.