Obsidian is at least storing in markdown. Although some plugins probably add additional formatting that isn't standard.

My use case isn't likely to be a personal knowledge base, I've just never had any traction on that sort of thing beyond a blog/microblog. I'm wanting to use something specifically for organizing the building of a shop/ADU: todo lists, pinterest-like inspiration boards, costing spreadsheets...

You don't lose anything from the proprietary nature of Obsidian because it's just markdown files all the way down.

Logseq was captured by VC a long time ago. They switched from open files to a database, their synching product is closed source (not selfhostable), and they have built-in telemetry.

Logseq isn't abandonware - they're in the process of rebuilding the app from the ground up to be database-driven, rather than house-brand Markdown as the source of truth and a database constructed from the files afterwards.

I'm not saying it's the most likely project to survive, but they've been working in quiet mode for a good while now.

For the sake of staying a computer nerd I decided to put all my notes in a private GitHub repo with help of a local 5b Gemma4 LLM. Is working extremely well. It doesn't matter in what format i type. I Use opencode for entering new notes.

https://anytype.io/ is the open-source CC of Notion AFAIK.

I wrote a more detailed comparison of Notion vs Obsidian here: https://bryanhogan.com/blog/notion-obsidian-comparison

I kinda dislike where Notion is heading though, forcing more and more things on their users without any ways to disable them. But yes, it's capable to do what you are looking for.

Maybe Affine could also work though, you can self-host it and it's more customizable: https://affine.pro/

FYI: I spent around 30-45 minutes trying Anynote, trying to match what they were showing in the introduction video (a todo list of tasks, where each task was a list), but it looks like creating a new space results in standard objects like "Task" needing to be recreated; the new Space had like 2 standard objects included. So I switched over to Notion and in <5m I was able to get going.

I was just trying to get a list of building supplies, one of which was the doors I wanted to use, to have a page where I could put a link to the product page for the doors I found.

Anynote looks promising, if I could understand why I didn't have what look to be the "standard objects" in a new space.

But all the Joplin data is not in Markdown files sadly.