It is not you, its Medium. There is literally no SEO on the site. You can't type in key terms into google and have your articles pop up. The only way people can find your articles you drive your own traffic to the Medium site. It would be better to set up your own Wordpress site and hire an SEO company to drive traffic to it. It shouldn't be this bad, but is.

My last article on Medium got six reads, and only 60% read through. So maybe three people read the whole article. Meanwhile.... I have a Youtube channel and just gained 10,000 subscribers and over 200,000 views in the last month. Which platform do you think I'm going to devote my time and energy to?

I never thought I would make a whole lot of money on Medium, but I thought I could get some feedback on my writing so I could improve. Even that small feat is not possible on Medium.

My suggestion is to post both on your own website, and to Medium, and to stay active on Twitter to push eyeballs to your writing. Or find a good (not scammer) SEO company to help you. Medium has become a platform where the juice is not worth the squeeze for most writers.