Yes, Microsoft put some effort in glTF support and it works great.
(I’m not familiar with the workflow from idraw, but I’m not surprised by the lighting issues if the scene actually has negative scales, it’s a pain to handle in some cases)
In the glTF file from Sketchfab, the model is split across 253 meshes, is it what you expect when importing it into a software ?
The original model doesn’t seem to be animated so I would use Blender to prepare the model using tools like https://blender.stackexchange.com/questions/3390/how-to-select-objects-based-on-materials if needed, and then export into OBJ.
OBJ is probably the best to achieve this since it’s simple enough. Let’s just hope it will not mess up the geometries because of the negative scales