Texture glitch: High level guidance needed

Set the material blend mode to masked:

338670-screenshot-1.jpg

and then you can just use a black and white texture to punch holes:

Caveat - I am new to Unreal.

I am importing the geometry from Rhino as a FBX. The surface has stencil like cut-outs. And it looks awful. I am assuming it has something to do with the mesh being all funky around the cut-out. But I don’t know if that is true or how to make it better.

Tangentially: I assume this cut-out effect could be done with an alpha map – it’s important for light to go through the cut-outs. But would not know how to start in Unreal, any pointers and or tutorials would be so appreciated!!!
Thanks you!!!