Yes, GPULM uses CUDA cores to compute static shadowing for baked light maps.
RTX is not used for this process at the moment. But maybe, as I mentioned in earlier posts, it could be used for an instant light map bake cause nVidia has already tested this solution.
You just wait few seconds and you have baked maps with - for example - 15 diffuse bounces.
Maybe Luo and the Epic team will change some in bake process to avoid UVW unwrapping for light maps.
I think that already used light maps system could be improved by automatic smooth MIPMAP upscaling lower resolution ones when the camera is going toward the surface.
It will give more blurred shadows at close range but you will not see the “pixelation” of low resolutions light map.