The first thing that comes to mind to me is WPEngine or other high-quality hosted Wordpress solution. You can install a plugin (from the web console, it's very easy) to post to social media, and there's another plugin to cross-post to Medium if that's your bag.

EDIT: I was wrong about Medium. They sunset that a couple years ago. You can use their import tool explicitly, or manually copy your post in and set a canonical link to your blog. That sucks.