How to modify in runtime the materials of a downloaded USDZ file and save it locally?

I am trying to configure the materials of a downloaded USDZ file and then save it in the Documents folder as a new USDZ file.

Currently, I am using the ModelEntity class but I have two problems:

  • I should modify the materials by using their names, but this class just seems that I can access the list of materials and eventually replace them but without knowing their name;
  • I have no idea how to save it in the local Documents folder as a new USDZ file in order to pass the URL to the AR QuickLook controller to display the modified file in AR.

Probably I should change my approach by using other classes.

Could anyone give me some advice on how to proceed to achieve my goal? I would really appreciate any help.