if you lower the resolution of the game window (playing in windowed mode and resizing the game window), the mouse sensitivity will increase, making it so you need to change the in-game sensitivity every time you change the resolution (game window)
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duplicates 1
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Thank you for your report!
However, this issue has been closed as a Duplicate of MCPE-22136.
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It could be because the game adjusts to the small area for camera movement.