Flurry of Fists
You know that the best way to get through an enemy's guard is to overwhelm them. At 3rd level as a bonus action you can spend a Combo Die and roll it to make a number of unarmed or Brawler Weapon attacks equal to half the number rolled (rounded up). These attacks do not generate or lose Combo die on successful hits or misses and do not add Punishing Strikes or modifiers to its damage.
No Opening No Guard
Your attacks have become some rapid that enemies can't find an opening to strike with. At 10th level if you focus all of your unarmed on Brawler Weapon attacks on the same creature that creature cannot use their reaction in response to your attacks, but in exchange you cannot make reactions this round.
Chip Away
Your attacks keep enemies on their heels and reduce their defenses. At 14th level, if you would land three or more unarmed or Brawler weapon attacks on a creature in a single turn that creature suffers -2 to their AC and Dexterity Saves until the end of their next turn.
Piecemeal Devastation
You've found a way to maintain the speed of your strikes without reducing their power. At 18th level your Flurry of Fists attacks adds your modifier and Punishing Strikes to its damage.