I dislike this Oilers team as much as the next Kings fan, but no, McDavid is not immature and full of himself. He's pretty calm and collected, actually. He's also the best player the league has seen since Gretzky and Lemieux. The dude just scored 152 points in a season! Also, no, Gretzky got just as much if not MORE love than McDavid. He was a household name even in America in non-hockey cities. He was on the cover of countless magazine, cereal boxes, video games, you name it. You could argue he is responsible for the existence of the majority of expansion teams since he entered the league.
The only difference is that today, if you are an avid hockey fan, you are flooded with hockey news because of the internet and its algorithms. You are consuming every bit of hockey news on a daily, hourly, minute by minute basis in a way no one in the 80's and 90's could possibly dream of. So maybe it feels like you are being exposed to McDavid hype more than Gretzky, but your perception is skewed due to technology. And the hype is deserved. He is THAT good.
Now if you want to talk about other players on the Oilers being immature I can agree. Nurse, Kane, and Draisaitl have clearly shown that they are undisciplined and whine every time they get caught commuting obvious penalties. The Oilers absolutely have the talent to win the cup, but if they don't reach that potential it will be because of dumb stuff like what Nurse and Draisaitl pulled in last night's game, NOT because of anything McDavid did or did not do.
I'll get down off my soap box now