One of the most common flaws we see in the golf swing is when the arms lift off of the ribcage and get steep in the backswing. While you don’t need to tuck your right elbow, there is some connection that needs to happen with the upper arm and the side of the chest.
You can use a variety of assists, but a pool noodle works well. You’ll tuck the noodle, headcover or other object under your armpit, and you’ll notice that while you’re not tucking your elbow, you are keeping that connection through the top of the backswing.