Hi, Danielle, it seems you are contradicting yourself. Now you are saying it not really about the app, but is about the style guide, whereas in your question you are blaming the app for the issue you are having.
As has been stated, Research Notes is the correct level 2 header, notes is incorrect. If you wish "Notes" to be a header, it needs to be level 3 or even 4.
I don't see "Research Notes" to be limited at all and, as Kay has said, it does not need to be in English so long as it is another language version of "Research Notes" and not simply "notes" (which is incorrect).