When I say 'series' I mean in the American not British sense. Like the British series Hustle has 8 'series' instead of 8 'seasons'. So not that kind of series.
Kuroko no Basuke and Takagi-san each have 1 anime adaptation consisting of 3 seasons (excluding movies). You can see that's how they're listed in the sidebars of their resp original pages: Kuroko and Takagi.
The Quintessential Quintuplets and Kaguya-sama each have more than 1 anime adaptation. TQQ has Gotoubun no Hanayome and then 'Gotoubun no Hanayome ∬'. Kaguya-sama: Love is War, Kaguya-sama: Love Is War? and 'Kaguya-sama: Love Is War – Ultra Romantic'. In the main Wikipedia pages they are listed in sidebars as like separate adaptations.
So eg 'Gotoubun no Hanayome ∬' looks not really like a '2nd season' but more like a sequel series. I don't mean parallel spin-offs like Once Upon a Time in Wonderland or sequel spin-offs like Yu-Gi-Oh! GX. I mean something like idk maybe revival seasons like Heroes Reborn that's treated as a sequel series instead of 5th season. What's going on?