I will never again build any kind of workflow for my knowledge on top of anything that isn’t open source. 5y is a long time and 10y is an eternity for these sorts of products but its just a fraction of my working life.

My own personal setup is a bunch of markdown files and it’s great, so I like that approach, but I’m very cautious about investing time for something so important in a product i don’t control.

100% this. The peace of mind I get knowing that all of my data is under my control is worth it, after scrambling to archive content from failed or pivoting services, removing my data from businesses that try to exploit it or trying to migrate my data from one old app to a different newer app.

There are many different open-source and self-hosted wikis, note taking apps and mind-mapping tools. Some of them are listed here[1], just Ctrl-F for "wiki", "notes" and "knowledge"

[1] https://github.com/awesome-selfhosted/awesome-selfhosted