The color of the displayed model is inconsistent with the color of the original model

Since you are using React then I am not sure if this might help you further, in case if you decide to stick with using OBJ+MTL models, but check this topic for my version of OBJ+MTL viewers.

The standalone viewer has custom MTL Loader and OBJ Loader embedded and it can load your model as a zip file but first remove that _MACOSX folder from it or just use the zip attached below for a test.

1-18.zip (3.0 MB)

Here is also a picture of that viewer with your model loaded.