SelectOARShader.cs is invalid, when imports glTF/glb files using glTFast for Unity.
Do not use OARSelectMaterial plugin, when imports glTF/glb files for UE5.
The glTF/glb files for UE5 with skeleton information violates the glTF standard (due to a bug in UE5). If you want to get same general glTF/glb files with skeleton information, please output it for Unirty.