what one or few changes to Homestuck would've lead to a better ending with less deaths. Also do you think there is a first Horrorterror or like some grand supreme swole boi leader

Well, there’s a Noble Circle of Horrorterrors parodying the Outer Gods of the Lovecraft Mythos, so there could be a Yog-Sothoth or Azathoth of sorts, but in general it seems it’s more of a Group of Horrorterrors than a centralized kind of thing. Not that it matters much since they’re all pretty much dead by this point.

Less Deaths though, it would require heavy chances to character personalities and such, everyone in Homestuck sort of Acts like they’re predisposed to? Hell Terezi’s entire arc is about her regret about the choices she took, and then, about missing the choices she didn’t take, so little personality or choice changes could have drastic results that would’ve altered the way the story developed. Something as simple as Nepeta not being impulsive enough to go after Gamzee, or Equius choosing to stand up for himself.