What do you mean “they dont allow this on the eternal realm”? The legacy item thing?
@topic
I think that the addition of 3 new mythic items is to strengthen the foundation and a sign that Diablo 4 will continue the current direction.
The devs seem to understand that players are reaching the end goal of having purple items too quickly and are trying to give them more variety. What they choose to ignore is that all their work on itemisation below the mythic level will turn into garbage in the minds of players.
One of the reasons is that a player can just swap the overpowered stuff onto any of their class/alts and automatically have BiS from the start. The game will soon have a BiS purple item for every equipment slot, so you don’t have to bother going for anything else, which makes boss runs more and more important with each addition.
I am also not a fan of this and pointed out the issue in more detail here: