Perhaps instead of every building being exposed upon using the (Building Vision), (Building Vision) could perhaps only expose the inside of buildings within a limited area. Maybe a 10x10 grid exposure, or a more sphere like shape? So that anything within the exposure radius becomes visible to the player, but not the buildings around it. (Similar to a spotlight)
My theory is that when all the buildings become exposed, the game has to now visually render the objects for the player? That perhaps by limiting which buildings are now openly visual to the player it would require less processing power.
I don’t know if this would work or not. Lemme know.