I think you’re mistaken about what this lower price tier offers. It is still ad-free, except for Youtube Music which is ad-supported. If a regular YouTube video uses a song that belongs to the YouTube Music catalog, it will have ads as normal. Also, this tier doesn’t offer background playback (with the phone screen turned off).
For me, the page doesn’t allow me to scroll past the first sentence of the article.
Maybe it’s because I’m using mobile Firefox with uBO? I only managed to read the article through here.