Maybe I'm not understanding the problem. I just saw mention of obsidian being the only paid app a user had on their laptop. I'd never heard of it. For me, I keep a notes.txt either local to the project (not repo) folder, or named similarly. To find something I grep through them all. It's not perfect but it's very easy. If it becomes collaborative, I push it as a readme or a wiki page. I don't feel a need for anything more. Maybe a slightly better search but that's it.