How to get ahead in the campain

Hi everyone,

I was looking for some advice on how to move foward in the campain, i am currently at the end of chapter 30,

Power Is currently 360.383,Nikke level is 250,my squad is :

Modernia Liter Laplace Asuka(Evangelion) Eunhwa

About gears almost all of them are overload and level 5 however i don't change effects, because i don't know how the Gear formulas work and sometimes i end up getting lower power when i try,same goes for harmony cubes i select them but don't know how to use them for specific type of nikke,about dolls,all Epic and at level 15,for Laplace i use Her favourite item.

i got a Lot of nikkes rn especially some i know many people use:(Rapi Red Hood,Red Hood,cindarella,Siren,Blanc,noir,modernia,liter...)

so i wanted to ask if someone could tell me what should i do,maybe someone can help telling me a Better team to use,or how gears formulas and Harmony cube works if there is a guide that explain it clearly

Thanks to anyone who can help 🙏