If you have an image where you like to add a Sunshine effect, one easy way could be:
1.open your image (attached my example) and identify the origin of the light (in the example 0,0)

2.add a layer and blend a striped gradient with yellow/red stripes like Mandelbulb_281 (attached),
with a conical sym shape starting at the light origin point (0,0 in the example)

3.set layer mode to Luminance, opacity to something around 50.0
4.add another layer and blend a striped gradient with yellowish stripes like Mandelbulb_227 (attached),
with a radial shape starting at the light origin point (0,0 in the example)

5.set layer mode to Softlight, opacity to something like 35.0
Play with the opacities to fit your taste.
That's it.

Outcome with opacities set to 50.0 and 35.0

Thanks Dinasset, I'll practice this effect, too.