Which Markdown Editor Do You Recommend For My Application?

Hey all, right now I am building a minimal flat file cms and I am looking for a nice markdown editor. There are two main requirements:

• The cms is for non-techies, so the markdown-editor should have the option to bridge the gap with some kind of optional wysiwyg mode.
• On server side I use extensions that support tags like [TOC] and integration of KaTeX, MathJax and other special stuff, so the markdown syntax of the editor should be extensible in some way.

Right now I thing about:

• Slatejs: My favourite so far, similar to prosemirror but easier to start with (based on react).
• Prosemirror: Looks good but learning curve is pretty high I think.
• SimpleMDE: Pretty fast, more traditional and based on codemirror, but I don't think that it is easy to extend?
• Tui: Looks good but also a bit obscure. Based on codemirror, too.

Which one would you recommend for my requirements?