Sifu

Imo the easiest arena to get this one in is the very first one of the very first pack: Night Call.

The 3 stamp requirement is to stay at or under Age 23, which means you can die a total of 2 times across the 4 waves within it which, once you see the spread below you will probably agree that this requirement is aggressively lenient, especially compared to some of the later ones!

1. Wave 1: 7 regular Henchmen; should be easy enough to take out with only getting hit maybe once or twice, if at all. I recommend saving the weapons and all of your focus for the later waves
2. Wave 2: 1 Juggernaut & 4 Henchmen; Juggernauts have a punishing grab move so if you have a hard time avoiding that: dispatch this one immediately with a weapon and go to town on the other Henchmen.
3. Wave 3: 2 Henchmen Bosses (Skull Brothers), 3 Henchmen. Immediately try to pick up another weapon and face smash focus attack the skull brothers to dispatch them. Henchmen are easy enough fodder.
4. Wave 4: 2 Juggernauts and 1 Elite Henchmen: By this point there should be at least two weapons left on the stage and various items that you can use RB on to knock enemies down. If you have any focus left from the previous fights: use it to demolish one of the juggernauts to ease the situation.

A Gold 3 Stamp Video is provided below for those who prefer a more visual approach (All credit to Pruitt Gaming for the video).