My brother, what you need is Obsidian if you're looking to create a knowledge repository digitally. I've been ranting off and on about Obsidian for a bit, and I use it for everything - D&D planning, my personal journaling, and my work knowledge.
It's free, it's insanely easy to use, and you can see how your notes connect to various concepts and such.
RE: Fit By...50? [Podcast]