Thanks for sharing! I think it might help to study welding a bit more, good welds vs. bad welds. Unless you're intentionally trying to emulate a certain look? What's your welding reference? It looks a bit to blobby to me, so I did a quick web search of "good weld bad weld" and found some examples that might help:
Your problem is on modelling side. I see same huge shading gradients on your mesh too. And while normal map can theoretically counter-measure them in a perfectly "synced" workflow you would never get it looking perfectly right in actual game anyway . 8 bit normal map with compression just doesn't have enough precision for…