On a side note, if there is ever a situation where you really need to steal from someone in DOS2, turning on the second player controller and distracting the target with a convo worked really well. Obviously haven't tried with BG3 couch co-op, but it is something worth trying if you have sticky fingers.
Don’t need co-op for that. You can just start a conversation with one character and switch to your pickpocket while the NPC is locked on your first character.
I have stolen from many merchants this way.