I think starting as frictionlessly as possible is a really good idea. Something where you can just easily type plain text and link those thoughts together – that’s the best place to start. For me that meant org-mode because I use it regularly anyway.
It’s evolving now with org-roam in the mix, in a direction I’m really happy with, but I think if I’d started trying to get everything in one I might have fizzled out. (That happened when I tried org-brain before – it was just too much friction).
I have some notes on my progression of wiki tooling here: https://commonplace.doubleloop.net/20200317105640-wiki_tooling