>>19098235I would say level 70ish since you'll begin tackling extreme raids and event challenges at around that level. Also it's 3x a day not 6x, sorry.
https://bluearchive.wiki/wiki/GameplayHelp_FAQsThis guide says to max level but considering the exponential AP costs to level up post 70, I personally wouldn't. You should also clear as many normal missions as you can do you can get the cafe upgrades early since they'll increase your passive AP gain by a lot.