You kind of need to make your own material:
- make master material that gets all textures as parameters (its like material template)
- make instanced materials for each set of textures (for each material exported from substance painter)
- apply those instanced materials to meshes
I am guessing but for dinosaur looks like roughness/metallic/AO material is incorrectly applied (like wrong mask to wrong type of input).
That is why i suggest you try one after another (like use only R and see if its really ambient occlusion, because it may be roughness there)
Alos that roughness/AO/metallic texture, it is best practice to add multiply by some scalar for roughness and metallic, so you can control those trough parameters.
And watch some tuts about making materials with parameters.
You need MASTER material like this:
Then make instanced materials and apply your textures to them, then apply those instanced materials to meshes.