>picks hardest difficulty
>think it'll be easy
Hi, welcome to the Pokemon Reborn community, where the Pokemon games will shit on your life.
Insane difficulty is ridiculously hard, and you'll need to prepare counters to ever gym battle. It is possible but there are quite few choices in terms of what Pokemon/strategy to use. Well maybe that's not fair to say. A more accurate phrase would be "there are a few popular team comps/strategies that work well against some leaders". I played on Reborn difficulty because I didn't want to pull my hair out because of a game, and I found it quite difficult but not impossible. Yes I lost a few times, but I just went back to the drawing board. Quite a few times I had to train a new Pokemon to help with a gym.