>>32172570>ORAS allows you to design your own Gym, or your own Trick Hoise, at will.You could place a few mats with predefined functions into a few predefined base layouts.
Comparing that to making a custom Gym is like comparing Mario Maker to a ROMhack of a Mario game. You can't even define the teams for your "grunts" or force the player to battle them at all when they enter your Gym, they always use randomized 'mons from a short list of randomized 'mons.