Fur/Hair particles look flat shaded in rendered view

So on my model, I’m using a particle system to create fur on my model (which is a paid asset so I cannot share the blend file, unfortunately), and it looks normal in all views except rendered view. It looks like it’s flat shaded and I haven’t been able to figure out why this is.

I’ve attached a link of the settings for the particle system:
https://imgur.com/a/OaZd49E

As far as I know, the old particle system has been depricated in newer Blender’s versions. There’s a new hair system, I’d suggest you to watch a tutorial down below on how to work with that:

The hair system is horribly unoptimized and doesn’t seem to work with my model. Every single action causes Blender to stop responding, even on my 7950X3D/4090 system with 64GB of RAM. I went through all the trouble with the particle system, so it would be so much more efficient to just solve the flat shading issue.