> and any conclusions therein, evaporate.

I'm in a similar but different boat: my brain remembers the conclusion but discards all of the "useless" details used to arrive there. This works fine on a personal level, but when someone challenges your position, you find yourself unable to defend it because all of the supporting details have long since evaporated.

So PKM might be useful to archive away the details after you reach a conclusion.

I highly, highly recommend having your own private wiki. It is the 80/20 sweet spot of PKM.