On tabletop I play a Way of the Astral Self Monk with defensive duelist. I thought I'd try that in the game and switched Astarion to open hand Monk. I'm not sure if I'm doing something wrong but it never seems to activate.
Monks can use weapons, but not Open Hand. Elemental monk works better with weapons than bare-handed in BG3. I don't think any martial weapons are also finesse weapons, though.
Poor phrasing in my part. It's not that they can't, it just wouldn't be useful since the main abilities do require you to be unarmed in at least 1 hand.
I don't want to be a contrarian, but I can't find anything in the PHB that says you can't wield a weapon. Unarmed strikes don't even need to be made with your hands. Is it a sage advice that I'm unaware of or something?
I was aware monks can (at the very least I was aware of Kensei), I'd just never considered it as advantageous enough to go Defensive Duelist, I guess.
In an MP save I'm in, I'm playing an open hand monk and am currently using that staff you can buy from Auntie Ethel in the grove because of the bonuses to unarmed damage.