Hello Artists, We are trying to achieve photorealism, please guide us with the reference image attached below. thank you and regards.
Try a HDRI.
Tough job the architecture is not great.
Lot of detail to the surrounding also needed, and or a photo to match it into.
Furniture and planting to the balconies.
I think the lighting arguably is the only thing that actually IS photorealistic in your image. You can try different HDRIs, or parametric sun and sky, but most it can do, is to change the mood of your rendering and not add or detract photorealism to/from it. You need to work on other aspects of the render, like models, materials, details, signs of tear and wear and so on. Currently your scene is very sterile, you need to add more life in it if you want more realism.
That was the first thing that jumped out to me too 