The question you’re asking really is ‘what is the right keyword density?’
The problem with keyword density is that it’s built on the philosophy that Googlebot is dumb.
Well, thanks to RANKBRAIN and its more recent core algorithm updates, we really can’t say that Google is as dumb as it was 10 years ago.
And given its heavy use of artificial intelligence and machine learning, it would really be dangerous for somebody to assume that Google was dumb, is dumb, and will continue to be dumb.
So, I would suggest that you stop thinking in terms of keyword repetition and keyword density.
Instead, focus on what your target keywords truly mean to the end user.
Ask yourself: why would somebody enter these set of words into Google when searching for information?
What’s stopping them from using other words?
And if they did use this set of words, what is the most likely outcome that they’re looking for?
Think in terms of questions!
What kind of problems would this person have?
What kind of questions would they have?
And if you start thinking along those lines, then you would produce those content that would answer those questions and also address related questions.
When somebody enters those keywords into Google, sees your content, and stays on your site, Google interprets this as a success.
The searcher found the answer that they’re looking for.
This should be your focus—not fixed ratios, percentages, or density.
Focus on the experience of finding value in a page.
That’s what I’ve been doing, and my recent projects have been doing quite well because of my focus on keyword search intent.
Keywords are still important.
But, you have to focus on what they mean for them to truly serve you.