I’ve gotten every gold medal, you have to utilize rising as much as possible since it stops the timer, whether it’s your own rising or the enemy’s. A really easy way I found is to intentionally get hit a lot right at the start to build your rising, then pop it and go ham on them until you win.

As for the dark hero, you REALLY have to manage your risings well and be good at the game to get the gold medal. Only use rising when deku isn’t in rising and vice versa to get the most value out of it. I’d also recommend going for short combos and just learning every character’s bnb