Choppy sensitivity on lower frame rates

Does the issue occur on Featured Servers (Hive, Mineplex), singleplayer, multiplayer or Realms?

Yup

Please, be more specific and point out, on which severs exactly the issue is occurring. Example:

Featured Servers - Yes

Realms - No

Singleplayer - No, 

etc. 

it occurs at every world, server and realm

From what I see in the video, you are using a mouse with an android device. 
What android device and mouse are you using exactly, its model, OS version?
I could not reproduce on my end. 

TECNO LG8N, Android 12.

Change your FPS to 40 below.

You need to run and jump, then look around.

It doesn't occur if you're just standing still 

Relates to MCPE-16688

Can confirm in 1.21.0. But i was able to reproduce it with touch controls