It’s not the privacy of the content we’re discussing, it’s the horrible Discord client that keeps datamining your PC. It even inspects all the processes.
I agree that Discord isn’t a good choice for FOSS projects for various reasons including privacy, but can’t you just use the web client to avoid that specific issue?
What I really like about Obsidian is that it stores your notes as plain text/markdown files on your computer. So you always have access to them, even without Obsidian itself. Markdown is also a fairly common format, so it shouldn’t be too hard to move them somewhere else later.
But your concerns are still valid and I generally also prefer free open source software.
If I had a Rappen for every time I’ve heard this joke I’d actually be as rich as you all think Swiss people are.