Markdown to HTML is already supported. On KO's FM long press on a markdown file -> convert.
It should support almost anything highlighted above and the conversion should be pretty fast for the kind of files I would expect to be in markdown (ie: not long sacred books
).
There's nothing to improve in the parser (unless you spot a bug) other than speed, if that's required. In that case I would suggest
https://github.com/mity/md4c. The best project out there, hands down!