My personal AOTY was Oshi no Ko. There is a lot going on in that show, even just tonally between drama, suspense, and humor; but it balances everything so well, and it has some really well-written, complex women characters, which was awesome to see.
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Aqua is kind of an incel, but I think the parallels drawn between him and Ai's stalker are intentional, or at least that's the impression that I get after S1. Even so, his strange and convoluted relationship to Ai makes for a really interesting psychological dilemma, and he is a very interesting protagonist. While some of his actions are well-intentioned, he is also capable of some pretty abhorrent stuff. I hope to see something of a redemption arc for him, but wherever it goes, I think it will be a fun watch.
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Beyond some excellent characterization and great writing, the music is amazing, the art direction and animation are gorgeous, and the overarching mystery and supernatural twist make it extremely compelling.
Season 2 is one of my most anticipated upcoming anime.