Edited review:
If you only like onee-san, mature, big boobs type character, this game will disappoint you because the game mainly prioritize lolis more. Even lolis are stronger, meta wise.
Recent changes on guild battle meta that forces your party's main attacker to be superior over boss, requires investing at least 5 elemental main strong attackers are kinda turning off when your SS rarity attacker gets denied because not being on-element against boss (kinda similar to GBF when comes to guild battle mechanics where 99% damage reduction against elements that is not weak against to)
So, if you play for your waifu, but happened to be non-elemental type, you have to invest all over again and find characters that fit your taste, but not lolis, better quit this game. 80% of big boobs here are buffers, not attackers
if you want to consider continue playing the game, consider raising S rarity attacker while slowly raising SS tier attacker for guild battle for time being
Meta changes for guild battle is stupid
Requires high-end device to be competitive in guild battle meta
Otherwise, good waifu collecting game