GLB / GTLF 2.0 Uploading Issues

I’m working on a project that has a lot of guns skins. It’s been really annoying to upload textures one by one. I’ve used the the asset manager, but it doesn’t help too much honestly.

I’m more interested in Roblox’s GLB / GTLF 2.0 support, but when I upload with that file type, the surface appearances (despite having textures for all four map types) appears to only be the color map. When I upload the textures myself it looks correct. Is it something with Roblox’s GLB support? Or am I doing something wrong while exporting?