You want to create a translucent UI in such a space, but widgets don’t support translucency. How do you do that?
Widget components do support transparency, the background blur is the problem (unless something changed recently):
I don’t think I ever tried to pull off a Background Blur + Render Target combo - might work.
This is a won’t fix, sadly:
Background blurs cannot be used correctly in a 3d widget component because the scene behind it has not been rendered yet so it doesn’t have all the data to blur.
Solution, wait for UE5 