I hacked up something like this for Apple Notes. It’s far from perfect, but at least it lets me type Markdown-style punctuation and get the expect results. Think of it like a crummy Vim mode sort of thing.
https://honeypot.net/2024/01/17/making-notes-look.html
This is useful, thanks!
Glad it's helpful! I didn't go super far with it, but maybe it can inspire someone else to dig in and flesh it out.