Apple ProMotion Display - does it actually work for video?

I've been testing the ProMotion display on my 16' Macbook Pro M2Max and I have doubts it does actually dynamically adjust for video content! When editing in Final Cut pro and doing some 25P-50P editing it is jittery until I manually switch the display to 50Hz - which means it DOES NOT do it on its own, even when 25P full screen content is played. Same thing for YouTube - I doubt it actually switches refresh to suit the content currently on display. So my question to gurus is - what the heck? Is it same as Siri - lots of hype, but very little actual performance? Why won't my ProMotion display switch refresh to follow the framerate of video content? Do we have a software tool that would report actual current refresh rate of ProMotion display?