I love this app!! The UI is super fast and the demo is well made. I think either way you’ll find users, tho it is a crowded space - the most important part is whether you personally find it useful I think :)
I think you’d get a lot of the features people are complaining about missing, namely around mobile usage, by having this just be a GUI for editing markdown files. Markdown is amazing, it can definitely store all these states, and can be edited with a plain ol text editor if you don’t have time to write a phone app.
For an example of how powerful “a gui that stores its content as specialize markdown” can be, see obsdidian.