When a translucent (opacity-adjusted) 3D model is too shiny, it’s usually due to overly high specular reflection settings, an unsuitable shader, or harsh lighting.
Specular reflection controls direct light bounce—too much makes even see-through materials look glossy. Using a basic shader (not designed for transparency) or bright, unsoftened lights can also amplify this unnatural shine.
Try lowering the specular value, switching to a "translucent" or "glass" shader in your 3D tool, and using softer lighting—this often balances shine with the model’s transparency.