Gym defender suggestions

I think it would be cool if you could duplicate a Pokémon defending a gym if it has a costume. It would be so cool to see a gym full of 6 different costume pikachu or eevee or whatever. Could be a fun way to flex the more rare costumes in the gym, like a little costume contest. Also, i think it would be cool if every month or so there was a weekend or day where you could put in legendaries, mythicals, ultra beasts as gym defenders. It would be tanky as heck and annoying to overtake but it would also be another way to flex some rarer shinies. There really isn’t a way to flex those pokemon aside from using in a raid and someone notices a shiny raiding with them