I use gitlab pages which lets you use any static site generator (not just jekyll) and is otherwise just as good as github pages. I use hugo for ahelwer.ca although I really should get around to putting effort into learning/customizing the site instead of using the default gitlab theme.
Yes but GitHub is “another garden”, surely is way more open than Medium but you still have to rely on other resources (Microsoft), you are not the true owner of your content.
Instead, using my own VPS I can have the full control on my blog (yeah there are still the laws obviously).
Anyway Jekyll has some limitations with GitHub, but is a lot easier to setup, especially for the comments and builds.
Given that you have all your content locally and can push whatever you want as long as it's static, it seems like the only part you "don't own" is the maintenance.