Instancing Static Mesh for an entire level [Optimization]

So here’s my problem, I have made a level using modular assets, so all the walls are made of multiple static mesh, and the ground and the roof are made wife ground static mesh, I just changed the material when I needed. By the problem is having more thant 10000 static mesh in one little scene is causing performance issues, so I would try to optimize it. Here’s some screen to help u visualise the thing.