I have been trying to convert GLB to USD in JavaScript - some progress, some hiccups. For reference, I just used Blender to convert my GLB character model to FBX, uploaded to mixamo, downloaded an animation clip retargeted by Mixamo for my model as FBX, then did a right click in Omniverse 2023.2 beta to convert to USD. I then opened the USD file.
I get the same result if I right click on the FBX and do File Open.
This is the same file opened in Blender.
Here is the FBX file downloaded from Mixamo.
AvatarSample_A_mixamo_Sitting_Talking.zip (5.5 MB)
Note: I did get a reference file by using the OV Build of Blender to export as USD (with animation), which can open in OV.