Importing rig causes visible issues (Blender 2.8.1)

I recently downloaded a rig from Truong CG artist, and I’m having trouble properly importing and exporting the rig from Blender. When I import the fbx file (originally exported from Maya by the artist), I get this in the viewport:

The bones aren’t properly set up with the model and the materials are, by default, a mess. However, when it is rendered using Evee it looks like this:

The artist doesn’t do conversions, unfortunately, so that’s out of the question. How can I correct this issue?

(Note: I’m trying to export the rig into another fbx file so that when I import the rig into Clip Studio Modeller, it’ll read the 3D data and rig correctly.)

Here’s the blend file:

The original fbx file I used can be downloaded from here:

(Sorry for the big files!)

i have same issues with blender 3.5. How did you solved the issues?
Thank you so much for your quick response