I've seen so many variations of "On-Page
SEO Gospel" that I completely avoid thinking about it.
The only
SEO-like process I use in writing is focussing on using both American and British terminology.
Write to draw in the audience, and write with passion about the subject, and you can't really go wrong.
I think people focus too much on the "implied" rules of writing, when Google is just looking for good, relevant, interesting and informative sites to offer. I don't think all the
SEO in the word can help if the content is just not interesting enough.
Whatever gains might be made in on-page
SEO tactics, it's probably lost in poor readership and engagement anyway.