This looks much more like a dust spot than sensor damage.

Dust on the sensor or low-pass filter typically appears as a soft dark blob, especially visible at smaller apertures (higher f-numbers). A good test is to stop the lens down as far as possible (for example f/22), defocus the lens, and photograph an evenly lit plain surface such as a wall or ceiling. If it’s dust, the spot should show up clearly in that test.

If it were sensor damage from the sun, you’d be more likely to see damaged pixels or other electronic failures rather than a blurred spot. The built-in sensor cleaning function may not remove stubborn dust, so the fact that cleaning didn’t help does not necessarily mean the sensor is damaged.

So based on the symptom shown, dust is the most likely cause.