Best way to render 3D animations in Swift from Maya - swift

Question

I've got two apps, one in Unity and one in iOS (created using Swift in Xcode). For the Unity game, our animator exports the 3D models from Maya into an fbx file which we are then able to render in the game.
Our challenge now is being able to render those same animations in the iOS game. I've read documentation that iOS supports usdz files. However, I'm having lots of trouble exporting the fbx files into usdz. These are the things I've tried:
I had our animator export the Maya file into Blender and then had them export to usd, which I then ran converted to usdz through Reality Converter. However, nothing shows up in the SCNScene (just a blank screen).
I downloaded all the appropriate SDKs from Apple and Autodesk to try and convert the the fbx file directly to usdz through Reality Converter, but when I run it in Swift, the textures seem to get messed up (we have a second layer of texture for eyes). Some fbx files turned out better than others. The below was the best one I could get.
Lastly, I created a .scn file and dragged the different dae/usdz files into the scene which I'm able to see in the scene editor, but when I load the scene using SCNScene(named: "filename"), I get an empty scene (with a sky and ground though).
Worth mentioning, I've tried converting the animations to dae and gtlf files as well, but with no luck.
I've tried two permutations of code to load the animations into the scene:
directly into the scene:
guard let url = Bundle.main.url(forResource: "ferox", withExtension: "usdz") else { fatalError() }
let scene = try! SCNScene(url: url, options: [.checkConsistency: true])
and also using an intermediary MDLAsset:
guard let url = Bundle.main.url(forResource: "ferox", withExtension: "usdz") else { fatalError() }
let asset = MDLAsset(url: url)
let scene = SCNScene(mdlAsset: asset)
There has to be a way to do this since fbx files are so common. Can someone tell me what I'm doing wrong (or even where, since there are so many different steps)?