foundryvtt-mindmap VS kanka

If you know your way around Docker or can set up a php -environment you can host Kanka yourself.

Here is the github repository. There is a bit of a tutorial there but I don't know how good it is as it did not exist when I was building my instance (I also think it uses Docker, while I just host on Windows with WAMP).

Here's the Github page

Yeah, you can find the github here. I use Wampserver to host it.

Open Source, and easily self-hostable ideally via a docker container similar to kanka

We also use kanka.io as a player resource. They take turns writing the journal entry for the current session, linking up NPCs, locations etc, and making notes of the stuff their characters learn and/or figure out.

I use https://kanka.io for my games and you can create a custom calendar there. You can add weather, moon cycles, seasons, all the fun stuff.

I use https://kanka.io to manage my campaign, if you're familiar with World Anvil it's the same idea. Like a wiki site for your game.