Lots of Obsidian talk here. As someone who started with the OG https://zim-wiki.org, I tried Obsidian and never found it compelling enough to switch.

I did, however, with Logseq.

On the surface they're deeply similar -- but Logseq's native handling of outlines -- including collapsing and and expanding on the fly (org-mode does this as well, but you know) is absolutely killer. It's the first one to kind of reliably "free" me from the whole "every note is a page" thing that causes lots of friction.

I think it could go well to solving op's problem as well. Quick expanding and collapsing and easy search helps me to poke around older knowledge in a fun and useful way.

(actually, I didn't "switch," I still keep day-to-day important stuff in zim, but for that storing and exploring old knowledge, I'm now all about logseq).