If you are trying to make a smooth animation, there are key points you are missing. 1: You focused on 1 part, that being the arm. 2: You somehow made the entire animation feel shaky.
Here's a 3-step guide on how to properly animate a smooth scene: 1: Make a low frame animation, focusing more on where and how they are moving over them moving in general. 2: Add in-between frames between each frame to give it smoothness. 3: Look for parts that seem choppy and add between frames to clean the animation. If you want to make your own, here are some examples: Brick by: @TheBaminations: https://scratch.mit.edu/projects/1193299106/
