One thing I feel most adult beginners would benefit from is an easy, short take back and hitting the ball with relatively slow, perpendicular racket face, aiming at 3ft net clearance. Who couldn't do that?
But no, most beginners I see at court just can't wait to do all the fancy moves, flip, swirl the racket all over the place and hit the ball very violently. That's too hard and discouraging when only 1 or 2 out of 5 balls make it.
Here's a good analogy/exercise that works extremely well for me. Get in a swimming pool at near chest depth, open your palm and sweep slightly below the water surface. Make the biggest waves or move as much water toward the front as you can. You would take back both your arms above the water so you could turn it faster. This is good for several reasons. It's tennis technically correct. Physically you'll experience great resistance, perfectly safe to try as hard as you can and won't injure yourself at all, you'll find a way to pivot better, employ your body for more power, and the water makes your standing a little unstable, kinda like running in the court while being tired so you can learn to stablize your whole posture. Exercising in water is generally great for the joints anyway.