heres an idea on the earth conquered/save part. its a split. just like how we spend stardust on upgrades and even DM. we can use those very resources to the planet (ironically if we really wanted to it could also lead to a change in how we see the planets we already have. for instance we currently farm resources off the planets but what if after we destroy them we actually rebuild them?) and thats what Segways into the whole earth saving mechanic split where we are attempting to build the planets stronger so the eaters couldnt actively destroy them (this could also lead to a defending mechanic where 1 planet that has been rebuilt gets attacked by eaters and we have to actively protect that planet. *this type of thing would happen maybe every 5-10 minutes* and when a planet isnt protected it doesnt get completely destroyed *just set to the minimum of 1HP* but does have to be actively healed which would cost resources) tbh this feels like it would strangely to some degree solve the DM over-farm issue since the planets could use it as the resource for rebuilding/healing. since the planets rebuilt status would be reset each prestige (aside from earths for the reason of having the defense mechanic to always be active but its stats are reset) and it could also lead to a system where you start at a future planet thereby skipping earlier ones (these skipped planets would be classified the same way as earth in the defense mechanic since they were skipped their defense would always be active but stats would be reset each prestige) and this is just the start of the idea of defense and rebuild that i can foresee *tangent/off topic* i told you i'd let you know when i get an idea lol.
oh and you could add a deployment of the guards for each planet rebuilt (primarily the guardians associated with that planet *ie novas serena for the novas serena planet* the guardians would defend the planet and it would be a successful defense but the defense would take 2x as long as the active defense *guardian stats are halved for defense and is why it would take twice as long but would still lead to a flawless defense if at max stats* deployed guardians would also allow for autohealing of said planets so long as one had the resources *there would be 2 paths for this 1 would be DM: requireing about 1/100th of its stardust value and 2 would be the stardust: price varies based on how destroyed the planet is*)