I’m pretty sure that AsciiDoctor has done most of the legwork already with their CM6 plugin: GitHub - asciidoctor/codemirror-asciidoc: AsciiDoc mode for CodeMirror
Since Editor extensions - Developer Documentation says that “…an Obsidian editor extension is the same thing as a CodeMirror 6 extension”, this shouldn’t be too hard to convert to use with Obsidian…right? Speaking as somebody who has not created a plugin (yet).