A big butt is masc. Ever seen baseball players? They got nice big butts. They get scouted at least partially on the sizes of their butts.
You will not exercise your way to a truly enormous giant butt. If that’s your goal, I’m sorry that you likely won’t achieve it. You can exercise to a big ol nice butt that can turn heads but I wouldn’t worry about it being “feminizing” cause… plenty og hot dudes have big butts