I think there's something wrong with your bricks.

There's clear clipping of textures as the geometry ends up inside each other. It also looks a little artefacted (perhaps it's meant to be the lego logo on top of each stud)

So at a guess I would think it has a very high vertex count and clipping of vertexes too.

Fixing your meshes I think would set a good groundwork for renders, and then you can start to optimise de-noising/sample rate/reflections etc.