Any idea why the textures can’t be seen even though
it’s on material preview mode?
Be sure they have any shaders with textures applied… and you have the images…
Try Vieport Shading (Dropdown) → Color: Texture or even Vieport Shading: Rendered…
…or switch to texture Texture Paint or Shading workspace…
Also check *File → External Data → Report/ Find Missing Files *…