S2 had Star orchestrate her own downfall and become a victim of her own massive negligence that allowed her enemies to beat her. It also introduced a massive slew of intrigue, character development, and PLOT with a cast of secondary characters everyone enjoyed.
S3 decided to become something completely different, talking about racism for absolutely no reason and assassinating characters to make them fit molds to fit plots to fit narratives that didn't exist in the show prior to S3. All of the mystery was similarly shattered by providing half-baked, poorly-executed explanations. Furthermore, Starco not being endgame, or at least avoiding it from happening at all in the show, caused a love decagon that makes Dawson's Creek look small-time.
S4 went all-out on its anti-racist narrative, completely flubbed the final antagonist, slaughtered some of the best characters in the show and destroyed relationships to make bad characters look good, and culminated in a literal multiversal genocide so Star could get second-hand spic dick that a closing AMA confirmed results in Starco never being a thing.