I am trying out a new program for, writing, note taking, outlining, and many other text based operations. I was drawn to it because at its core are flat text files stored in .md format (Markdown). This allows zero lock in as .md files can be read by any text editor.
It has a user extendable architecture and many folks are writing add-ons for it.
Obsidian is the private and flexible writing app.
For all platforms, including Linux, and phones.
@corlin I've been using Obsidian for a couple of years now, and am really happy with it - though I do (of course) wish it was open source. (I've tried a few OSS alternatives, including Logseq, but none worked as well for my process/workflow as Obsidian does.)
I'm impressed enough with Obsidian that I pay for syncing even though I'm already leveraging the community Git plugin to sync with a private git repo as well.