My frustration with them was always more about what I felt were lapses in the narrative than them as people. In some ways I think the writers were a little unfair that they oft used Xander to kind of gaslight the audience like in Dead Man's Party or Into the Woods. Like Dawn, I get why the dislike is there but it's one thing to dislike a character, it's another to spin every single thing negatively.

fandom loves to talk about how she's twice the hero that Xander and Willow ever were

Pfft, yes. The whole there-should-have-been-a-crossover-so-the-Scoobs-can-be-awed-by-Cordy's-awesomeness thing makes my eyes roll.