The easiest gun for a beginner to learn with is the same gun that shoots the best for anyone. Good sights, a great trigger, ergonomicly well designed with good balance, accurate, and has little recoil.
Single actions fit this criteria better than double actions due to the short trigger pull and long trigger pull on DA guns. It doesn’t matter if the pull is as smooth and light as stroking a chunk of soft butter on a DA.
Learning to line the sights up before pulling the trigger is what learning to be accurate is all about. Some people just can’t figure that part out, it doesn’t matter how many bullets are in the gun.