There is no rule written in stone for how many times you should use primary keywords in your content. But as I said, you should use them enough to signal to search engines what your content is about, but not so much that it becomes keyword stuffing.
In general, it is recommended to use primary keywords a few times throughout the content, including in the title, headings, images, and throughout the body of the content
However, the exact number of times will depend on the length and nature of your content. Rather than that what’s important is to focus on creating high-quality, relevant, and useful content for your users than on including a specific number of keywords just to meet the threshold.