It uses Notion as CMS, the blog posts are stored in a Notion database with additional properties like description .etc
Disclaimer: I am the author, let me hear any feedback if you try it
I went to self-hoseted/self-rendered Jekyll, with Discourse embedding handling comments, and it's been working fairly well so far. Cloudflare caching covers traffic spikes fairly competently, and if I want to host the content on something else, I literally just have to upload the rendered files.
As a bonus, it now works perfectly well without cookies or Javascript. Not perfectly, there are some JS features that improve things, but it should render and be entirely readable, with images, without JS.
A lot of individuals and companies are already using Notion and this makes it easier for them to write blog posts with it.
I know that for developers like me and you markdown is everything we need but non technical people need something more high level, just the act of embedding an image in markdown is very difficult for them
I would say I'm personally aittle dubious of the only two options being free and $50 a month. You might want to consider another price point in there in between. Although I'd do see that you're still in beta so I recognize the prices might not be final anyways.