This is important as PS5's VRR support at 60Hz drops out at 48fps, so dips beneath this will look jarring - otherwise VRR saves the day in terms of game fluidity. If the quality mode is struggling ...

The first is simply a variation on the method employed in film projectors, with the display repeating frames to increase 24fps content to 48fps, 72fps or even higher, thus eliminating any flicker ...