It's a few things that you need to work on. I can't see your toss on your serve, so I can comment on that. Tossing hand needs to stay up, knees need to bend more on trophy position, the head of your racquet needs to be pointed up right before you get in backscratching position. Also work on racquet head speed, what you called acceleration. Start by looking on YouTube on all these things I mention one by one. Take your time and practice, practice and practice. If you want to get better it will take time.
I don't scratch my head unless it itches and I don't dance unless I hear some music.