Can you make so that you can buy the upgrade materials? farming for them will suck if you need lets say a rare resource or even legendary one and the drop rate is low so it will take some time to get just one and the game will turn into a grind sim with some extras on top, (i say this mostly because of the boss battles that you may add) or make so that you can get them in a passive way like you have someone or some app that can buy it for you