What non-FOSS software have you been unable to quit?
For me, Google video search, Google books (Internet Archive is good, but doesn't always have the same stuff), Adobe InDesign (but in the process of learning LaTeX), and Typewise. As for the Google stuff, I liked Whoogle a lot, but almost all their instances seem to have been blocked or shut down. Also, apologies if this is repeating an earlier post.
I'm really liking Logseq. I started on it instead of Obsidian since Logseq is FOSS. I understand it's not too hard to switch over since they both use markdown files, granted some scripts need to be run to convert markdown differences between the two.
Logseq's business model is to charge $5/mo for syncing on their (fully encrypted with a private key) server, but you can use a FOSS syncing solution (or a property one) if you prefer. I pay to support the project and to simplify sync on work devices I don't have administrator rights on (so most other sync solutions wouldn't work well.)
I tried Logseq, but it was slower than Obsidian and it's section/block oriented and I want it to be note oriented (Obsidian). It is a decent alternative tho.
This is the way. I started on Obsidian, and Logseq is painful in comparison. It's a good product, but I got accustomed to too many nice conveniences over the past couple of years.