I've been hearing about a Bell™ on YouTube recently, but I've not seen it. That's because I don't use the YouTube website or app, I use a AntennaPod and NewPipe.
So if you want to get notifications you can Subscribe, click the Bell and the Exclamation mark that they are adding next week. Or you can use a system that just works.
Firstly I subscribe in podcast app, example channel feed links by id and name.
However it's against YouTube's terms of service to download and so they don't provide the media in the feed, so you still have to use a YouTube app.I use NewPipe.
So when you are ready to watch videos, go to the podcast client, and click "View Website." Then the dedault app will launch.
Note: the podcast app has to support Atom but it's been a standard for 11 years.