When you add NaOH to the acidified water containing dmt salt, dmt turns into freebase, which is insoluble in water. So water goes milky
.
Once you pull it with HOT naptha/heptane, it clears up. The non-polar clears up too
Why you saw slowly decreasing pH is a question. Maybe the reaction with vinegar was not immediate.
I can assure you that water saturated with NaOH won't have pH less than 14.
I never measure how much NaOH I add, I never measure pH at this step too. I just add enough, which is maybe 3 or 4 times more than necessary. No problem at all, high concentration of NaOH doesn't hurt anything, you cannot add too much.
Acceptance of the fact that our reality is not real doesn't in fact mean it is not real. It just leads to better understanding what real means.