I have a serious issue on my fedora 36 workstation os. Videos often stops and become stuck at the loading screen on Firefox. However when I try to play a video file on system, the video starts playing like it should and instantly.
Note these also happen in regular use and it even sometimes freezes the entire browser.
It seems to me that you are describing a Firefox issue, in that other Fedora applications don’t give you this same problem. If that is correct, you might need a Firefox version change. What version are you running?