I don’t need to make a point that it is better to get free traffic from Google than paying Facebook for clicks. When you write content, you pay the price once (fixed cost) and get a return forever. When you advertise on social media, you pay every time you get results (variable cost.)
The main challenge is to write content that drives results. In the advertising space, as soon as you spend your first dollar, you get exposure. In content marketing, you can write a docent of posts without getting any visit in the short term.
Ideally, you can track down to the Adsense revenue or Affiliates purchases, but at first, it is better if you improve the top of the funnel (visits to your posts.)
There are two tools I recommend you to analyze content:
You can use the same tools to analyze your competitors content performance as well.
The first tool will tell you which content is performing better in terms of visit, and the second one how your audience is finding the content.
If you see a strong preference for let’s say GDPR, you might want to write more about it, until the next hot top comes up first in your list.