60 fps video is flickering when played with 6.5 beta 3 - looks a lot like the issues already mentioned here QTBUG-111459 and QTBUG-109213

Video plays fine with RHI backend set to opengl but outputs warning "failed to get textures for frame false" repeatedly.

Nvidia V-Sync settings and latency settings seem to have an impact (low latency / ultra latency). Sometimes the issue goes away after resizing the window or moving the window to another screen. This is, like the other issues linked above, related to the hardware decoding to texture. It seems as if the frame order is messed up and old frames are displayed again / in wrong order.