As keywords define each page of your site, you can use them to organize your content and formulate a strategy. The most basic way to do this is to start a spreadsheet (your "content to keyword map") and identify your primary keyword for each article. You can then build your sheet to your own requirements, add keyword search volume, organic traffic, page authority and any other metrics that are important to your business.
It makes sense, even in 2020 that this process of labeling is how you create a Search Engine Results Page out of pages Pagerank 2020 identifies, identify spam, identify monetisation trends and promote content first pages and user friendly content above others. You can also imagine that over time, Google should get a lot better at working out quality SERPs for its users, as it identifies more and more NEGATIVE ranking signals, thereby floating higher quality pages to the top as a second order effect. A end-result of this could be that Google gets an amazing SERP for its users.
Use the Keyword Planner to flag any terms on your list that have way too little (or way too much) search volume, and don't help you maintain a healthy mix like we talked about above. But before you delete anything, check out their trend history and projections in Google Trends. You can see whether, say, some low-volume terms might actually be something you should invest in now -- and reap the benefits for later.