In his first 6 seasons in the league, McDavid ranks 1st in points and outscored 2nd scorer Patrick Kane by 68 points.
In Jagr first 6 seasons in the league,(1990-1996) Jagr ranks 8th in points behind Gretzky, Oates, Sakic, Hull, Recchi, Yzerman, Turgeon.
He started peaking in his D+6 draft season, while playing with a healthy Lemieux for a full season.
McDavid is in his D+7. In his D+6, he was stopped by covid but had 105 in 56 games, fair to say he was peaking too.
McDavid has outclassed Jagr if you compare their first 6 seasons as far as dominance goes.