How can I get smooth reflections instead of these jagged ones?

Hi, I'm pretty new to unity and I had this problem with a couple of models I'm trying to import. It doesn't happen in the same scene with some others, and there are no visible differences between them in terms of polygon size, triangulation, etc. I tried searching for a solution but found nothing that fixed it so I just throw the question here, I'm sure one of you will have the answer. I pretty much played with smoothing groups and angles, optimizing the mesh, retopologies, other materials and so on. I'm just stuck right now. Thanks