YouTube's algorithms are a beast, but from what I understand, it all depends on views and how frequently you release videos. The more views you get, the more traction you get from Youtube, which gets you even more views. They also want people returning to their website, so posting frequently is a huge plus.
As far as an author on youtube, I think the success depends on your personality, what you're presenting, and how you're presenting it. For authors, I think the best content to have is practical advice. I recently went from Excel and Word as my tools of choice to using Scrivener. The more I used it, the more I wanted to do with it, so I looked up some "how-to" videos. Those videos tended to have a pretty good view count.
Writing advice videos do fairly well, too, but there are literally thousands of those, so you have to stand out somehow. I occasionally watch a channel called Terrible Writing Advice and they have 200,000+ subscribers and their views can get up to a million, but they present their stuff in cartoon form and obviously giving the advice in the opposite form.
So, it just depends on what you want to do with your channel. Talk about yourself and you books, don't expect a ton of views. I have a friend who was a fairly successful self-published author who was picked up by a traditional publisher who wanted her to start a youtube channel. Her other socials have thousands of followers, but her youtube videos never crack three digit views because there's no real substance to them. She talks about her books or announces if she had a giveaway, but there's nothing there to keep bringing viewers back and that won't even make a blip on Youtube's algorithms.
If you want your channel to be a viable source of advertising and income, as you said, you'll have to take a lot of time away from actually writing.
