I was willing to try Substack because I could try it for free. But also I heard that you could import your Medium articles. However, when I tried to import the feed, it did not work. So I published for about a year and then gave up!
Several days ago I got an eMail from Substack. I was surprised because I had never gotten an eMail. But like an idiot I clicked. It opened up to a site that looked like Substack. Nothing seemed suspicious. A few days later I got an eMail saying people were receiving bogus eMails from Substack. (???) (Sigh.)