I tried to get some attention to this issue in another post. The bug affects Youtube, overal Brave responsiveness and mouse gesture extensions. Both Edge and Chrome don’t suffer from this, so it’s not an underlying Chromium bug that could not be solved or anything.
My workaround for the time being obviously it not to disable hardware acceleration in Brave, as this would be detrimental for anything but bug reproduction. I also don’t like to disable the NVidia feature globally. So instead I set up the Brave profile in NVidia’s settings to disable the Background Application Max Frame Rate only for Brave. This seems to work, but practice will have to show if it is a viable long-term workaround.