An image would help. What exactly are you seeing? Are you completely sure you have each of the correct ORM values in the corresponding RGB channels? It might be exporting RMA for example (rough Red, metal Green, ambientocclusion Blue) Also, it's best to set up the same lighting environment in both apps, like using the same…
As you mentioned, I had an idea that the ORM texture set is not used with the default shader system. However, I was confused because I saw examples of asset packages using ORM maps without any shader customization. I am new to Unity, and as you said, getting into complex shader systems will likely cause errors at this…