Full screen video tearing in firefox Ubuntu 19.10

I tried following my own advice from this question, but the workaround there failed to work in 19.10 while it worked up until 19.04. The tearing (applying the tweak in the linked question) is reduced, only the upper part of the screen has tearing now, but it still isn't completely gone.

It is once again a firefox specific issue (chromium and the electronplayer snap don't have this issue). Are there any other workarounds to reduce tearing in firefox other than the aforementioned one?

I moved from Mint to Ubuntu 20.10 just couple of days ago. So not exactly the same circumstances but... I also faced annoying tearing when I watched full-screened Youtube videos in Firefox. My desktop's specs are pretty common I'd say - intel core i7 processor with UHD630 gpu. I tried a lot including most common advice that is to set Firefox's config option layers.acceleration.force-enabled to true. Unfortunately, this alone doesn't solve the issue. After quite a research I found bunch of Firefox's config options that finally solved the issue.

1. Open up about:config
2. Set layers.acceleration.force-enabled = true
3. Set layers.force-active = true
4. Add mozilla.widget.use-argb-visuals and set it to false
5. Restart Firefox

Now I can watch videos without an issue.

However, I don't understand why Cannonical doesn't do something with it, because it seems the issue is there for years. I use most generic hw and the issue is there right out of the box.

Hope this helps you as well.