Anyone ever used KDE QTcurve with 0% opacity?

Is there any newer themes that work the way this does? It’s way back from the kde4 era. I use the blur effect, and menus, toolbars and dolphins sidebar is completely clear. Many other parts are still solid color such as the folder background and most programs don’t use alpha on view areas.

I’d like a theme that offers alpha on the view area (by default where stuff has a blank/white background).