I hope you don't take this as a criticism, just feedback, because your product looks quite nice and if I weren't such a worry-wart, I'd probably subscribe.
My issue with all notetaking applications is that all of my notes are "very sensitive data" to me. I treat my notes repository like a combination diary, scratchpad (where I plop things like temporary passwords and API keys), and memory dump. I know it's probably unreasonable--you seem trustworthy at first glance--but I have this pretty big fear of my notes store accidentally leaking or even just an admin trawling where they shouldn't and reading stuff I've noted down.
Like you, I'm still on the hunt for "the perfect notetaking system" but my A-number-1-highest-priority feature requirement is self-hosting on my own hardware. If you offered that, even for a fee, I'd probably buy it because it looks quite nice.
Same here. I'm currently using Joplin (https://joplinapp.org/) for note taking, which syncs my notes via WebDAV to a server under my control. Supports markdown, but if I want to publish certain notes, I have to manually transfer them to the website.