This looks like something usefull. Some observations after first start…
I really like the idea of your app. Could be a good companion for my PrimitiveNotes plug-in for Roundcube. Hopefully you find the time to develop it further.
By default, according to the RFC 6238 standard, they are generated every 30 seconds. But this time step can manually set to faster intervals. However faster as 30 seconds is not very user friendly. RFC 6238
If you have access to a Roundcube instance, you can try my PrimitiveNotes plug-in, if you want. You can find it at https://codeberg.org/Offerel/Roundcube_Primitivenotes. Maybe this helps to understand, for what and how i use markdown notes. I have absolutely no knowledge about flutter or Android coding, so I can’t help that much.
But I can test and send you a little bit feedback for your app, because I really like your concept so far.