You are not alone, there’s been a few conversations about non-functioning media widgets and some components (like Ace Editor) on Safari Desktop and Safari/Chrome on iOS.
When I get a chance, I will modify the below bug request with your notes on the video editor as I’m certain these issues are related. (or you are more than welcome to comment to the bug with your notes)
My current theory is that mobile browsers on iOS have some kind of “feature” that requires some extra flavor in the HTML or JavaScript to prevent websites from running rogue or battery consuming scripts, audio, or video (but it’s not immediately obvious to my novice front end development knowledge). Safari for desktop is built heavily from a mobile mindset since Apple has been iOS first for a number of years so the same “feature” in iOS that is blocking this content ends up blocking in in MacOS as well.