Gif is playing fine on my phone via vger.app
There are some extensions you can try - https://duckduckgo.com/?q=old+reddit+extension+firefox&t=fpas&ia=web
But I’m using LibRedirect - https://libredirect.github.io/
If you’re using Firefox mobile (Android), you could try this https://github.com/octonezd/oldlander
Yep i know a lot of people at least in my country. If not YT, then they get it from FB
This is the way