Should you post your content on Medium? No.

I'm actually working on a decentralized alternative right now! I didn't expect custom domain support to be so in-demand. Would love to know any other "must-have" features on your list?

I too am interested in the answer to this question.

Wordpress and Drupal are my standbys. (Self-hosted or cloud-hosted.)

Buy domain: NameSilo.com

Get cheap shared hosting plan: SiteGround

In the admin panel of the hosting plan, you can point and click to install a free Wordpress site (the hosting company will do it for free if you contact them). Once it's installed you can point and click to choose a theme.

It takes a little time getting used to everything, but anyone with no coding or technical skills can do it

I'd take a look at static pages.

Go to forestry.io, create new page from starter template. You now have a working blog with source on github.

Then go to netlify.com, create new site and hook it with your github repo. You now have free hosting.

Add custom domain to netlify hosting.

It's about 20 minutes total and you get SSL, global CSN, autopublish on every change, every change as commit, all data in plaintext instead of database (no platform lock in). Super easy version of AWS lambda as a bonus.

It requires zero technical knowledge from writers and gives all the possibilities to technical people

These are all good options that require no technical expertise: https://write.as https://ghost.org https://wordpress.com

Personally if you're looking for something no more complex than Medium I'd just use the WordPress.com paid plans. No membership or sign-in required for your readers and pretty much anyone who has worked in blogging has a knowledge of WordPress. If you're willing to put in the effort and try something new I'll second the Forestry/Netlify approach above with the caveat that it might still require some training if you want to do anything fancy.