From what I’ve seen you could try and re-create the base mesh, with a triangulation setup, and then copy vertex colors from it by nearest neighbor from the new mesh, and then hide the original.
The tricky part would be creating a bounding volume, similar to the way collision is done, and then re build the geo.
I think he’s wrong as to the limitation of blueprint, if anything the C++ implementation could be faster and more optimized, and could take advantage of existing libraries for building proxy geo, but blueprint could be easier to deal with if / when code changes to the engine come along. But I think blueprint is very flexible, it’s just like normal code if you start having to build your own classes, and functions, it can get messy quick.
Either way it’s not for the faint if heart.
The real question is why you wouldn’t build the geo the way you wanted it, with LOD’s in maya, vextex light / color it, and then import and light it further in Unreal ? Why build high poly geo, just to decimate it ?