Using the Safari extension on all Youtube URLs

Is it possible to change the extension to make it work on every URL? 
It was quite possible with the previous userscripts solution. You can check it out below.
https://gist.github.com/asportnoy/628b820184297f5fe296c1a5b79c8000

I have seen on your code that it checks if the website has “/watch” in the URL, maybe removing that would work without breaking the whole code? 🤷‍♂️