Improving performance with light obstacle behavior

In a maze game I’m building I wan to create a field-of-view effect where the parts of the maze that are visible from the character’s POV are lighter, while the rest of maze is darkened.

However, when I attach the LightObstacleBehavior to the tilemap sprite that I’m using for the maze walls, the game starts to lag to the point where it’s unplayable.

When I remove the LightObstacleBehavior performance is much better, but the immersive effect is gone.

Is there a way to improve performance with the LightObstacleBehaviour? Or is there another way to create a similar light blocking effect?

Thanks for your help!