So a bit of a correction - “Season 4” is not a season. It was a movie split into multiple episodes and the OP is more showing the characters all celebrating that they are having a movie. Also while it’s not been officially announced the Kaguya-Sama Twitter has noted they are working on a Season 4 (as this is only half-way through the manga and there is plenty more to do)
The "Season 4" opening that is actually the movie opening has a lot of references to skiped chapters of the manga Examples being the 4 Heavenly Kings of Lamen (running gag) in the theater or images of Kaguya and Shirogane's first date (chapter 3) in the outdoor And yes, opening 2 is the BEST
