What FOSS applications do you use for habits, tasks, and notes?

https://lemmy.selfhostcat.com/post/432780

You really sound like the taget for Logseq
A privacy-first, open-source knowledge base

A privacy-first, open-source platform for knowledge management and collaboration.

logseq
Thanks! Could you expand?
You can write anything in the daily notepad and link it to any concept or page anywhere, and have backlinks, and it builds a graph of all of this. It can handle TODOs as well
How can you sync it though? I am running Linux and iPhone. Only paid sync?
You can sync using syncthing or anything else or use the paid sync feature