I chose a nature scene to have the sunlight coming through.
I then created a second layer and selected the Polygonal Lasso to be able to select the area the sunlight would hit.
I right-clicked and chose fill selection. I changed the contents to “background color”. For the blending, I chose “linear light” with a 30% opacity to make sure it wasn’t too much light.
I then selected the eraser and chose the “Soft Round 300 Pixels” brush with a 53% opacity to blend the edges to create a more natural light.
This is the final result.