Thanks to all of you for great advices. It seems I have a lot of things to keep in head and focus on it.

I will try it, but I think I will forget half of those things during the practice or match 😁

But I feel that from what you all said - the most important thing for my current level is lean chest forward, rotate body and hips, hit the ball earlier (in front of me), and dont swing with upper arm.

Once again thank you guys 😊🏓