RST is pretty much the worst option out there. Your mainstream options are:

* Markdown. Great for simple stuff. It's going to be awkward if you're writing a book or technical docs or whatever.

* RestructuredText. Better for more complex documents but the Python code that drives it is abysmal and it's less popular than Asciidoc so there's really no reason to use this.

* Asciidoc. Definitely a step up from RST but it does have syntax weirdnesses, and the way parsing is done is a messy pile of hacks. Also Asciidoctor is written in Ruby which makes it horrible to work with. But tbh still better than RST due to the low quality of their Python code & docs.

* Typst. Definitely the best option for complex stuff except that its HTML output support is still experimental. You can make it work nicely with some fiddling and custom CSS though.

Overall Markdown and Asciidoc are the best options today, or Typst instead of Asciidoc if you are forward-looking.

This thing just looks like a slight tweak on Markdown which is completely pointless compared to the pain of .. you know, not being supported by any other tools at all.