Baldur's Gate 3

Open hand monk 9/thief rogue 3

Tavern brawler, cap str

They badly fucked up at math and made tavern brawler OP: it doubles your strength mod to hit and to damage. With 20 str, that’s 10 + proficiency bonus, you will only miss most enemies on a crit fail. Even with disadvantage you have like 80% hit chance against mobs in good armor. Stack bonus damage and it’s pretty easy to be doing 20-25 per hit.

Thief Rogue gives you a second bonus action, so you can do 4 attacks plus ki detonation completely resource free:

• action (attack, attack)
• bonus action attack
• bonus action ki resonating strike
• free action detonate ki resonance … it’s about a hundred damage per turn that’s all considered magical damage, and forces 5 concentration checks.

But you also have 10 ki per short rest! For 1 ki, you can use flurry of blows (topple, usually) to attack twice with one bonus action. Why topple? If they fail, all of your attacks after that happen with advantage. Burning ki, you can do 6 attacks, and probably pop a crit or two, for a reliable 120-150 damage along with a good chance of whatever bonus effects from the open hand maneuvers.

I usually don’t even use flurry of blows twice per turn, though, nothing my monk is next to survives that long unless they’re a boss.

Edit:

I forgot that you can spend an action once per long rest to regain ki and get another bonus action for 3 turns. So full nova that’d be 8 attacks and force 3 topple saves. It also basically requires no gear, but there are some nice bonus pieces, so you could just spec everyone this way and punch the absolute to death.