Sounds like it could be all sorts of things, gonna need more data to work by. What CPU are you using? Also, one of my best friends always had a new technical problem with his computer every day, almost uniquely due to his own fault by meddling and tweaking with things because that's the kinda person he is. So the solution was often that some other software he had installed for curious purposes was interfering / messing up. Do you run any other software that either provides an overlay in game (Overwolf, discord, nvidia geforce, etc...)? Any apps that are claiming to boost performance or "clear ram usage" such as CPUcores, Afterburner, etc? If so, try turning all of that off.
I know CPUcores causes a ton of issues with the Divinity Engine 2, and if that is prone to being affected by outside influences, then sure as hell DOS2 is too.
