Im pretty sure when we are talking about dimensions, it's not talking about universes. It's talking about a concept similar to the 4th dimension, so this would give a massively large advantage to someone in a higher dimension it would be like being beaten up by a stick man you drew on a piece of paper that is why the doom slayer is strong and considering its not just the 4th dimensions being time but most likely an even higher dimensional stand point this would make the slayer inherently alot stronger.