Every Custom Virtual Controller (even the one in the Demo Project by NReal) causes heavy flickering on the phone. It seems like every second frame, an old frame is being displayed, e.g. when moving the pointer, there is one dot at the fingers position and another one lagging behind by 1s.
It does not seem to affect functionality, button presses get registered correctly, it just looks like the button is being triggered every frame when pressing.
TLDR; Set Blit Type to Always Build Settings>Player Settings>Player>Resolution and Presentation>Blit Type = Always
androidBlitType was set to 1 when I installed NRSDK 1.8 in a fresh Unity URP project and caused the controller screen to render at 60FPS, eventho the custom controller is throttled to a 30FPS render. I believe that caused half the frames to use stale information, hence the flickering. Ensure that the ProjectSettings.asset file contains androidBlitType: 0 for everything to work