Aero Glass Blur performance

Hi! Wanted to say that this is an amazing project :)

The Aero Glass Blur plugin when enabled causes a fair amount of repainting lag on KWin. I'm on a RX 5700 XT and wayland. Easiest to test is opening and closing tabs in Firefox or another web browser - the opening/closing animation will be really choppy and will take longer.

The built-in KDE blur plugin or taj_ny's fork does not have this issue, so I think this is related to this code specifically.