Are you lucky with the items obtained in the field? I play for 12 straight days at the abandoned iron mine, playing 18 hours a day plus 6 hours in spirit mode, and I was unsuccessful.
I used the 2 soups, outlaw mode and no items.

Damn that's pretty unlucky. Feel sorry for you. Is your character maxed level? The drop rate buff from maxed level seems to be quite exponential even though it is only 10%. Before max level I barely got any notable drops. At maxed level now been getting better drops. Got 2 oranges and a couple of yellows over the course of 2 weeks.

yes, i'm at maximum level using 2 soups mode and outlaws.

I've been trying to drop equipment for 18-6 hours at Cron Castle for exactly 13 days. Yet only  7 8 pieces of purple dropped equipment, not yellow not orange :). Is the probability of equipment drop rate 0.0001%? Seriously terrible. I used 2x soup and the cron castle loot level 10 !! After a while, the game no longer gives pleasure...