Thank you for playing and your kind words!
Since 5.4 it actually is :D I leave the guide here:
https://dev.epicgames.com/community/learning/tutorials/w6l7/unreal-engine-custom...
I had to tweak it a bit, because I did not need circular but "cylindrical" gravity. But worked very smoothly.
Jumping off the side does work, but I also didn't manage to do it consistently. It's right on the border of impossible. I think one has to get really close to the sun, but I will definitely tinker more with it, so it does work more often.