When you view the model in the Sketchfap viewer, click on the "Model Inspector" button and then enable "Vertex Normals", then you can see that the right shoulder of that character indeed has inward-facing normals. This is a mistake in the model, not with the way you import it. Such a mistake is easy to make, because many 3d modeling programs have two-sized rendering enabled by default (to improve usability), while most game engines do not (to improve performance).
You should be able to fix that in Blender by selecting the shoulder and flip the normals.
But if you really don't want to mess with the model and use it as it is, then another option is to use a shader which supports two-sided rendering. How to find/create such a shader depends on what render pipeline you are using.