Optimized Complex Collision

Often a good method for generating collisions is decimating a duplicate of the static mesh. Like this cave hall which is single sided geometry
unreal will not generate a very good collision except when using complex collision as simple. It’s not the best solution doubling the poly count.

The Cave hall pictured below has 480 triangle Static mesh and 168 triangle collision, two separate meshes imported on top of each other. with the low poly mesh set as complex collision and render turned off. A single asset with the collision embedded would be ideal.

Does this have any benefit to performance or not?
Can somebody create a plugin to use complex collision on the parts of a static mesh with _UCM and turn off visibility for those parts?