I can't offer any dark web pointers, never having 'gone there' knowingly, but on reading your OP the statistic that the normal WWW comprises only 4% of the total tally of sites. I heard (3rd hand) from an IT security expert much the same, though around 10% was their estimate. I find these figures to be crazy, simply because if we think of all the websites from the largest to the smallest in the WWW have people behind them as a backstop, even if only one individual. Using logical reasoning, that would necessitate there to be either a whole order more humans on the planet currently unaccounted for, or every internet site proprietor having a great many dark web sites as a side hustle. Simply put the numbers don't seem to match up with the purported facts. Even if a great many dark web sites are bot sites controlled by some master site, it just seems to not make sense to me.