I’ve been using Obsidian lately. Proprietary with an open plugin ecosystem. Works well, makes it easy for me to integrate with other notes and such, but I haven’t figured out a good workflow for exporting work for submission. That said, it’s all markdown and there are lots of plugins for stuff like that, so it’s probably mostly just that I haven’t tried very hard.
In the past I’ve used Google Docs (proprietary), Scrivener (proprietary), Manuskript (open), Zim (open), and probably a few I’m forgetting. Really it just comes down to what you’re looking for out of the software, there are lots of options.
The biggest thing to keep in mind from a self-hosting perspective is local storage and easy backups under your own control. I use syncthing to keep my whole Obsidian vault synced across a few devices; for some software that’s easier or harder due to file formats and accessibility.
Considering there seems to be minimal changes to the game and the graphics honestly didn’t need any updates beyond what the GameCube could put out, I am still unreasonably excited for this game. I played the everliving fuck out of TTYD through my teens. Tempted to mess around with a danger Mario build for the first time in more than a decade.