In Matthews' D+1, as an 18 year old, he scored 40 goals and 69 points, winning the Calder and propelling his team to the playoffs for the first time (full-season) in over a decade.
What was Barzal doing in his D+1? Playing in the WHL. What about his D+2 though? Oh, yeah, playing in the WHL. This past season he was a 20/21 year old, sheltered rookie who you're comparing to a teenage Matthews, and despite going PPG behind Tavares, avoiding top match-ups, his team still missed the playoffs.
This same old song and dance happens every year and its comical. "Strome > Marner" "Brady Skjei > Rielly" "Aho > Marner" "Boeser > Matthews" etc. etc. It's as if the Leafs are the pinnacle, gold standard for every other team's best players to be compared to.
He's no McDavid, whose missed more games in his career to injury than Barzal and Matthews combined.