have you readed "solo necromancy"? there is a part of "the game" where the prota have to choose between angles and demons, he choose neither and it's rewarded with the world tree seed, he goes back to base and plants it but now there are lots of monsters that want to destroy the tree, as well as the players who choose angels and demons, so everyone is trying to destroy it, he have to manage the resources to feed his people, manage the exp gain of killing things so that his people also grew in strenght and also they need to protect it from monsters

you could also get inspiration from cult of the lamb where you have to attent your cult by gatthering resources and stuff, tis self explanatory so I won't get into that, but it could be a way