I finally found a workaround for the USDZ export, without having to go to my mac!
I actually found a couple of workarounds.
Just remember to convert your shapr3d obj file to GLB first using something like https://anyconv.com/obj-to-glb-converter/
2. FORGER (from the app store)
It´s only 9.99usd to download.
It has USDZ export.
You could even use it as a rendering program by painting your models in it
3. Sketchfab (there is a monthly fee though if you want to upload more than 1 without makin possible for people to download it)
Original pictures from Shapr3d