I'm not sure what's happening, everything looks fine in the material preview but as soon as I switch it to render it gets that ugly shading issue
Photos from different angles. These were taken in Rendered Preview, Cycles, GPU Compute.
I'm going to go with Z fighting or flipped normals. In overlays check face orientation. If there is any red then it's flipped normals. For Z fighting you can select the face that turn black in edit mode and press H to hide them to make sure there aren't any faces under it. You can also try hiding(H) object in object mode to see if there are duplicates of the case object. To unhide press Alt+h.
Sorry for the late reply, here is the file via google drive
Hi Jeremiah JJerryDoes3D ,
The main culprit is the Bevel Node in the Plastic Grey, orange and Red. Just disconnect it and those shading artifacts are gone (but so is the Bevel).
Now, I think the Radius, was a bit small, considering, that your Units are cm. Maybe 0.05 would be more appropriate, but even then, I can't seem to get rid of the Shading issue.
Might be some conflict between Shade Smooth By Angle and the Bevel Node...