Grand Colosseum not only acts as a difficulty hack to one of the hardest pokemon games out there, but brings a host of QOL changes, including but not limited to
Physical/Special split
Fairy type
65 New moves
Stat/type/Ability updates and changes (In line with Drayano's hacks)
Revamped TM list with 8 new TMs
Infinite TM use
New shadow encounters
Gym themed Colosseum battles
Higher difficulty
Alolan Ninetales and Marowak
Different versions based on which set of starters/legendary trio you want
Game data provided by IGDB