Oh yeah, both Joplin and NextCloud are great. I tried them both in the past. NextCloud is a bit bloated in my opinion though, I was hoping to go for something simpler both to install and to use.

Most of us here on the Lemmy Selfhosted community are skilled enough to keep a computer running somewhere, expose it securely on the internet (or just LAN, if that’s good enough), and install their own services such as Joplin and NextCloud, but my goal would be to make something that you don’t need to self-host. If you can trust any server, you don’t need to host your own. I like the idea of building a network comprised of both self-hosting users, and “normal” users, like here on Lemmy.

The federation may leave you wanting more and the collaboration might not be “real time” enough for you either, though. If you can build something better by all means go for it.

I’m not sure I understand what you mean. Do you mean writing a protocol that supports federation is a very difficult thing to do? Actually my first draft didn’t include federation as that’s just too much for my skills. But I am considering adopting Matrix, and Matrix includes federation, so why not? They built real-time messaging with Matrix, so I would assume that should be real-time enough for document editing.