Light Bleeding that I can't get rid of

I’m currently designing a level modularily, and all of the lighting has to be able to be turned off, therefore dynamic.
But I’m struggling to get rid of light bleeding that appears practically everywhere, except a few places.
The walls I’m using are double sided planes. There’s always two planes between rooms, since each room has their own set of walls. The distance between the walls are 2 units (I think).

This is how it looks. The player is able to use a flashlight, so I can’t bake the lights. The shadows would be visible.
I don’t need any particularly good looking shadows, but just something that works. As you can imagine, its very frustrating to play with the shadow bias and shadow filter sharpen for hours upon hours to no avail.