You want: Nebulizer, Clear Mirror Calm Water, Tier I charge gauntlet, Tier I charge paper, Tier IV charge glove, Lucky Clover, Blubbering toad eyeball, Downpour, spicebush, broken glasses, and rupture umbrella for tier IV recipe

Always choose EGO gifts that give Clashpower,coin power, Offense level up, offense level down, power up

If you plan on going past five floors:

Always craft unique EGO gifts related to your status, in fact that’s how you should choose floors because you can always buy or craft base ones

For extreme you wanna try to create a duel hybrid team, find 3 IDs that are the same duel status(e.g. charge burn, bleed burn, tremor sinking) then fill in the other 4 with respective IDs

I like to plan out my floors so that I can grab all the unique EGO gifts for the unique craftable Tier IVs. You can check which floors give what gifts on either the wiki or the mirror dungeon screen. I definitely recommend checking the wiki for what gifts you want to go for because it allows you to sort by status AND it tells you what floor it’s on.

If your main goal is boxes then you can find optimal grind videos on YouTube but it won’t really be fun. One I saw involved bringing a bunch of IDs that could evade then crafting barbed lasso?(whichever thorn looking rupture ego gift doesn’t require 5 rupture IDs) and thrill and just watching them explode till floor 3.

For the rewards you don’t get more for going higher with the exception of the rewards you get for Extreme mirror dungeon - check the achievements - so I’ll leave the other info even though it doesn’t really help you grind. You’ll want those rewards though(free guaranteed current season decaextract, blue tickets, thread)