upgrades

Hello, I started playing Olympus recently, got to Artist rank and I am curious if someone developed optimal way to upgrade your pickaxe? For now, I just horde my mana to by Divine which will speed up mana gain but I wonder if there is a better way.

I am trying to get the ore generation level 4 island upgrade but it won't activate. I have all the requirements; the money, the mana, and I am rank 7. It just says I can't afford this upgrade when I click it. I tried relogging, bu it still won't work. Please help me fix this somehow :(

I had a quick idea about how to actually implement prestiges to have more than just simple commands, and cosmetics. Per rebirth you do, it could open up a new pickaxe upgrade that you can apply. Now, you might say: But Demeter, Hades and Zeus rebirth actually do something, and I agree, it's just...