First, let's look at the lower body. In terms of weight transfer, you've done alright, your right heel has lifted up after stroke which indicated a complete transfer. But there're some mistake
- Overly bent knee, in some strokes your right knee bent to almost 90 degrees. The further you bend the more you will need to push your right leg to transfer weight, and it will cost more time to complete the stroke. Additionally, this also stress your knee and could result in injury. Try to bend it at an angle larger than 90 deg (as you did in this picture).
- Your weight focuses on the right heel, it's not desirable since: 1/ It limits the force you can impact on the ball compare to when you lean forward; 2/ In actual play you can lose balance due to reflex when facing an incoming ball. So try to lean forward by standing with the upper part of your foot (where the orange arrow points).
For the upper body, I feel like your shoulder is a little stiff. When you retract to prepare for the stroke, try to relax it more, if you feel your arm can drop to your back that means you've loosen your shoulder right. At the moment you hit the ball, tighten your belly and let your arm snap like a whip, then immediately relax to recover.
Edit: you hold the racket too close to the base, this could help you put more force into the ball but at the cost of spin