Also try to find websites linked to what you are writing about. For instance, for articles about programming, https://dev.to/ offers a very good platform, and so does https://hackernoon.com/. Both guarantee that you completely own what you write there.
But to me the best solution is still to have you own blog. Many platforms will offer you a Wordpress or Ghost blog for a small amount each month (I would stay away from free platforms, most of them still own your content), and if you feel comfortable with a little tech steps, you can try a static blog generator such as Jekyll or Eleventy, and host it on GitHub or Netlify.
For my blog (https://scastiel.dev) I use Eleventy, hosted on Netlify, with my own domain name. Works like a charm :)