Hello Cyaoeu. The following character assets were made 100% in Blender, and are directly compatible with the Epic male skeleton without retargeting.
Skeleton :
Direct linking to the Epic male skeleton without the need to retarget animations :https://youtube.com/watch?v=QAbqGGmmYCU
So yeah it is definitely possible. The issue is that users stumble over the (admittedly tricky) skeleton naming issue and then declare that the workflow is impossible or that the Blender FBX exporter, whereas it actually works very well. It’s really a bit of a shame because it spreads misinformation …