I feel you. The amount of issue we encounter when working with USDZ creates complication across all our pipelines. We'd really love to support the Apple Ecosystem but the lack of documentation turns USDZ, for example with Quicklook, into a never ending research cycle.
Just an example: I know USDZ is a much more complicated format then GLB. But in AR views GLB compression with WebP can slim down complex files (with AO maps) to 6-9 MBs, while USDZ remain at 30-50 MB, in many countries or even some regions in between good networks, a difficult experience.
Or bespoken AOs. To create a useful pipeline how AO Setup would work in Blender for GLB and USDZ, took us days of research. Or name the development for Reality Converter is slow and it lacks a lot of practical features.
No WebXR in Quicklook, where we are not able to add color changing buttons or similar to the AR experience, while that is totally simple with Android phones. These and many more issues we encounter make us often give the feeling what is Apple direction here, with AR Quicklook or Vision Pro in the end at all.
Please Apple, hear the mourning.