There's third-party keyboards like [CodeBoard](https://play.google.com/store/apps/details?id=com.gazlaws.co...) that makes symbols etc. easier but I'm pretty wary of installing keyboards given the number of permissions they get.
Another idea could be to explore long-press formatting options or a formatting menu on selected text. Still awkward, but perhaps easier to do.
[0] https://play.google.com/store/apps/details?id=org.pocketwork...
Also, did you plan to publish it on F-Droid ?
An F-Droid and Google Play Release is planned in the coming weeks.
I think it's Worthless to think/expect anyone to do notetaking with such horrible keyboard experience.
Great effort! But I won't even try it.