Were they trying to solve the mystery? Yes or no?You keep the missing the point somehow, If the main point behind an end goal is that a character's actions should to lead said end goal but they don't that's what as known bad pacing which P4 tends have throughout the entire game up to November. No action that the Investigation Team does up to that point leads to them closer to the killer's identity which is their goal right, Each rescue just adds a new member to introduce their quirk to you right, Yukiko likes laughing, Chie likes Meat, Kanji likes females, So does Yosuke and Teddy and Naoto gets embarrassed about girly things. I don't care about P4's cast outside of Naoto and Kanji because they don't show any care or reflection towards meeting their goal which is primary purpose of why their group exists. The slice of life stuff doesn't matter because it's not the group main purpose for existing, Solving the mystery behind the Murders, Catching the killer , solving the mystery the Midnight Channel and returning Teddy's World back to normal (Which every one in the cast, Teddy included forgets about).
Them failing to do so is a different topic.