I want buy something, but DP accumulate very slowly
The best way currently is repetitively farming Queen Bee in PvE
If you don’t have a good pve loadout you will die pretty quickly.
My all-in-one pve loadout is
Feel free to use and alter it to your preference.
A more complex guide on this method of gaining DP:
Invasion Events, Events, Frost Moon and Pumpkin Moon, Fishing