Relatedly, I have a greasemonkey script[1] that makes Snapchat on web much more usable. I just updated it to include this video fixer logic so now it's easy to scrobble videos and download them.
It uses the MutationObserver API to immediately 'fix' any <video> element added to the page. Really I should just copy you and make a version of it that just does the video fixing but runs on every site. It's crazy how browsers have a nice built in pro-user video element, but that every site intentionally overrides and degrades it...
Turns out this doesn't work on facebook or instagram reels. I only watch the latter on my phone but whenever I do open reels on web in the infinite scroll mode it does not work. it works on direct links to a particular reel though.
That's great. The one site I definitely need it on is instagram whenever I happen to open a reel on web. And I'd like it on reddit because its video player sucks, but it just adds it on top of it so I have now ended up disabling it everywhere else.