If the bright area stays in the same part of the frame across different lenses and settings, the most likely cause is a sensor problem rather than a dirty filter or front element. A damaged sensor can create a washed-out or overexposed section on one side of the image, and bright outdoor scenes often make it more obvious. One known cause of this kind of damage is exposure to laser light.

To narrow it down, try a different lens and remove any filter entirely. If the issue remains in the same place in every shot, the camera body is the likely source. Cleaning usually will not fix sensor damage. At that point, the practical next step is professional inspection or repair through Sony service or a camera repair shop.