Would a 3D Brick Wall be Aggregate Geometry?

I noticed in the UE5 documentation for Nanite, that it does not handle “Aggregate Geometry” very well. I also noticed when I did a simple test of taking a 3D modeled brick of about 20cm/10cm/10cm and used a blueprint to mass spawn a brick wall with the brick geo, I couldn’t really get a wall much bigger then 5m/5m without a hard cut in framerate. I do know my current graphics card is outdated now, but I still wanted to get more clarification on what all " Aggregate Geometry" might cover besides foliage.