This extension probably sitll works, but I switched to the Vivaldi browser so I now use Chromium. Adding "pp" (haha funny word) before the ".com" on YouTube usually works well enough for me when it comes to downloading videos.
A silly open-source extensionlet that sends your video trough an ad-free YouTube downloader when clicked.
There are only 20ish lines of code.
This addon is very simple, all it does is open up 9xbuddy when you click the extension while you're watching a YouTube video. Surprisingly, i could not find anything like this that was open-source so i made something myself.
I might make this addon do downloading client-side sometime, no promises.
PS: I have no affiliation with 9xbuddy. I haven't encountered any ads with their site so it's why I'm using it.
If you do encounter any ads I'd recommend using uBlock Origin, also feel free to open up an issue and recommend other sites.