I work in 3D commerce and have found it frustrating trying to create USDZ files without a Mac. I created an online tool to make this easier and I hope it helps if you're having the same problem.
Currently it only takes glTF as input (in packed .glb format, because that's the immediate use for my work), but I'll add more file formats in the future. Let me know if you have any issues/thoughts/suggestions!
