Marketing a book for self-published authors

As many of you, I've been doing a lot of research about this and making a lot of effort, with few results. Eventually I happened upon the following article, and am inclined to think I agree. What do you all think?
https://independentbookreview.com/2019/02/28/10-common-mistakes-to-avoid-when-ma...

I think it's super important to realize that 99.9% of the book marketing advice you'll find on Google, YouTube etc. is geared towards fiction authors. If you write nonfiction, it is so, so important that you ensure the advice you're following applies to your genre and niche.

>2 SkateGuard: So true!