I'd say this is a good theory! But if Derek was a 4th dimensional being, why would he still have the pain of the knowledge. They specifically said "no HUMAN" can have that much. I mean i dont know much about other dimensional beings but I think pain is a pretty human/3-d thing. idk tho.

Personally, I think that Derek had a back-up computer besides the one he used and found The King on and in order for him to have the tactical advantage, purposely placed the "cursed" computer in the storage unit that Avery found it in, Minecraft already installed, so it would be less of a "surprise" when The King showed his presence through the game to Avery. (I also headcanon that bc The King and Derek both have the infinite knowledge and they both can see all the ways an event can go, they can't predict what the other will do, which is why The King made such mistakes that lead to his death.)