I'm currently using the Foam extension on VSCode. It allows me to take all my notes in markdown and can see a kind of starmap of my notes which shows the link between related concepts. I tried Zim (a personal wiki software) and org-roam (same thing as foam but with org files instead of markdown and much more terrible "starmaps"). I still have to use it much to retrieve my knowledge, but I really like how it allows me to take quick notes so far and forces me to think of connections between things.

The problem I had as a programmer working on legacy systems intermingled with new stuff is I had trouble finding my notes about stuff. Confluence's search is basically unusable and there's quite some overhead in using it to take notes in the first place. Using Zim/Foam lets me easily find the information I need when I need it.

Basically, I'm just not gonna remember everything that might become useful months/years from now so I dump everything in my own personal wiki and make sure it's easy to navigate/find stuff I need when I do remember I saw something similar before.