Reduction of triangle count for overlapping meshes

Hello,
I would like to create an editor for dynamic mesh in UE5.4.2. I have created a Dynamic Mesh Component actor to which I add new meshes. I also created a simple brush, which is also a Dynamic Mesh Component, and when I press the left mouse button, I pass the Dynamic Mesh from the brush to the actor in the world and use apply mesh boolean. I have tried many options (I used ‘Remove hidden triangles’ for example and it not helped) and combinations of any other operations on dynamic mesh, but I can’t reduce the number of triangles when I add a mesh that overlaps other meshes. I’ll explain this with an example. Each added box, no matter how large, creates 12 triangles. When I try to cover the old box with a new, larger one, the triangles from the old mesh still exist. Is there any way to reduce those triangles?