Some spots are fine, others have seams. There are marked seams on the mesh, but the UV map is seamless, and removing the marked seams seems to have no impact.
Edit: No seam visible when looking at normals or tangent via a geometry node, nor when looking at the UV map applied to the model as color. I'm pretty sure it has to be something to do with the UV mapping node.
Edit 2: I've uploaded the file here.
Maybe it's from the mesh? In edit mode select all vertices and merge them by distance. It's probably not this but this has magically repaired my meshes too many times
No changes. :(
Hmm, does it have any colour when in edit mode? Maybe it's a crease?
The edge is highlighted in red, since I have a texture seam marked there, but the texture is seamless so it shouldn't be creating a seam from my understanding. I've uploaded a copy of the file here.
If you use a smooth by angle modifier and set it to 60° the line will dissapear, although it seems to mess with the reflection too, I'm new to this too so I'm not of much help.