Hi @Anonymous
In addition to the guidance you have received from other posts on this forum re Chamfer tension, unchecking Turbosmooth in .fbx export dialogue, etc. ) , which I will assume that you have followed in your current mesh, there is a thread on the Substance Painter Forum that mentions other factors that can affect baking normal maps.
https://forum.substance3d.com/index.php?topic=18717.0
Specifically, avoiding sharp 90 degree angles which you appear to have here (at least on several of the problem edges) and can potentially improve the bake by chamfering your low poly version on the problem edges to have the low poly more closely follow the hi poly geometry and avoid the 90 deg angles. Also, see the discussion in the above link regarding smoothing groups.
I cannot tell from the UV Map you posted where the problem edges are, but you can by selecting them in max with the UV editor window open and then zooming in closely to look for any overlapping edges. I could not really see closely enough from your image, but your UV map had some edges that seemed to be stair-stepped and possibly overlapping, so just zoom in and check that.
Lastly, after following all of the techniques mentioned in all of the posts and above link, I suggest you view the geometry from the same distance that it will actually be seen in your final work. It will often be possible to zoom in very close and expose anomalies that won't be visible in the final work. So if you have managed to minimize the artifacts and it doesn't show at the final distance, then from a practical standpoint you will have succeeded.
Hope this helps.
