So a monk can:

1. Attack, and then
2. Use a bonus action to attack again, but with an unarmed strike this time. Or spend a ki point and make two unarmed strikes as a bonus action.

I believe that's the way it works from what I'm reading and seeing.

But does that work if the monk is carrying a two handed weapon or a shield? Or does the monk have to have a free hand?

How do you think it will work in BG3?

Planning a build right now is very difficult without knowing how the rules work, lol.