Unrealistic expectations are the problem.
Kid wiill not be Vegetta. Kid will not be Killua. Kid will not be Grimmjow, or Sasuke, or Kawaki, or Bakugo, or Hiei. Kid has to be himself. He just beat a yonko, he's not being treated "badly"
He beat a yonko but Oda utterly butchered the fight.
He off-screened 90% of it and only showed a few panels of Kid and Law using big moves. Linlin deadass didn't use ACoC offensively even once on panel.
Kid was also the only member of the rooftop that didn't have advanced haki or a means to do internal damage and his final attack was profoundly underwhelming.
Oda also didn't let Kid get a good moment against kaido to avenge Killer and the fact that Kaido beat his ass. Like I said, Kid should have been given ACoC instead of awakening. That way, Oda wouldn't need to off-screen Linlin's haki and just leave it up to the readers as to how the duo dealt with it.
Kid would deal with Linlin's haki via ACoC, Law would do the major damage via awakening, Luffy being supreme has both awakening and ACoC.