Same here, did you find a solution?
Only the default example HDRI by Epic is sharp, and that’s only 4K. What setting are we missing? Why didn’t this work seamlessly?
Also, the HDRIBackdrop complains that another skylight is active, but if I remove that skylight (and directional light), my entire scene becomes black. So this is RTX only? That’s rather unfortunate if that’s the case. I saw a Youtube video demonstration where a guy from Epic used this in a helicopter scene on an iPad. Again, I wonder what setting I am missing?