LaTeX

Essentially, simply LaTeX (or Typst) support, mainly for math.

This is Markdown compatible (mostly), so no issues there.

You could have a separate type if necessary, one with a renderer if not selected and showing the raw characters if selected, or, instead of a separate object, simply integrated with the standard Note object. Additionally, when printing, exporting to PNG or saving to PDF, should show as rendered.

“https://visualos.featurebase.app/p/ux-basics-markdown-heading-support” has “In fact, support for all markdown would be a great.”, showing this sentiment is shared.