What version are you on? I have 2K21 on PC current gen and they double really well.
I also have 2K21 Next Gen on PS5 and they NEVER double team...it was, literally, removed by one of the patches. You can have 60 points at 3/4 time with Curry and there are no doubles. It is not position based, I have had games with Embiid where I have started 20 for 20 from the field and they NEVER double him.