terrible shadow quality

why is this happening? is it bcz of UV maps cuz I unwrapped these in blender.

Are you using static light? Then you need a much better lightmap on the wall.

light map resolution of the wall is 64

That’s too low looking at the size of it.

was just going to say it feels like a light map res problem, try overiding it to something higher like 512 and see if that remedies the problem then you can optimize