Could you share a glb sample model in private message that I do some tests?
We are going to phase out datasmith gltf import. Did you try an “Import into level” instead? With new interchange framework you should be in a good place to import gltf using the “standard” UE import.
But I would still like to test as we did not touch DS gltf import so no reason it was working in 5.0 and no more in 5.1