Ways to help reduce color changes due to lighting in Unity?

Hi everyone, I am working on a WebXR project through Unity, but I am struggling with lighting and asset colors. Whenever I run the game, the lighting will change the assets’ colors quite a bit.
Here is some background information: since this is a WebXR project, assets (mostly from tiltbrush and openbrush) are imported through javascript and socket.IO. That being said, we don’t use Blender or Maya to setup these assets before importing them to Unity.

What happens is whenever I run the game, assets’ colors are different from what they are:


What might be the reasons that cause this issue? Is there a way for me to fix it?

Thank you guys for reading this.

Hello! Which Unity version are you on? Could you post screenshots of the Lighting window, and Inspector when the asset is selected? I suspect that environment lighting is missing for some reason.