I installed DeoVR via steam and tried to watch videos, but pitch value rises automatically 0 to 180 and the image rotates even I put aside my Quest 2 controllers.
How can it be fixed?
Are you using Quest through a link? What happens if you just run DeoVR for Quest from Oculus store?
This is what a "Center" button is for. Always map a button in your controller with "Center".