It was the same thing for me, it seemed like there was a wall. Somewhere around 3 or 4 treasure it was just chests with junk over and over. Caves and hunting at night would be the 2 fastest ways of collecting treasure I think. Treasure maps are just as bad, more frustrating even, since they say treasure map and 50% of the time there’s no treasure. Half the fun though is how merciless the game feels.