Using Gyro to measure device angles

Hi to everyone, i need to measure actual device orientation on 2 axis using gyroscope.
My goal is, assuming that when the device is left on a plane, such as a table, angles are 0,0, and when i rotate the device i can see actual rotation around the 2 axis of the phone (i'm excluding the Z axis perpendicular to the screen)
It's very similar to have an air bubble level on the phone, that shows degrees.

Thank you very much for your help

 

So, what is the actual problem?

• Gyroscope.gravity
• Vector3.SignedAngle