Pettersson has done more with lesser offensive supporting cast.
You must be out to lunch if you think he's done more with less. Nylander has been the best linemate Matthews has had outside the 30 or so games he got with Marner this year. Nylander's best career season with Matthews full time has been 61 points. He came up as a rookie together with Auston and he was on Auston's line while playing through his snake bitten hold out season last year.
Outside of Nylander and a little bit of Marner. Matthews has played the vast majority of his NHL games with guys like Kapanen, Hyman, Johnsson and Marleau. None of whom come anywhere near players like Brock Boeser or JT Miller who had 72 points in 69 games while playing majority of his minutes with EP.
EP also has had 22 points on the PP as a rookie and 24 points this year in 3 fewer games than Auston. AM in his first 3 NHL seasons accumulated have 21, 13, 20 PPP. Leafs do have better players on the team compared to what the Canucks have however, Auston has almost never had the luxury riding shotgun with the top players. He's practically carried every line he's ever been on.
I can easily argue that this season alone, EP wasn't even the best Canuck forward. I think JT Miller contributed arguably more to the team than EP did. Even these playoffs he's been a huge catalyst. *I know Markstrom is your MVP.
Auston has been the best Leafs forward and the guy who does nothing but score clutch goals and carrry the team for 3 out of the 4 years he's been on the team. His only down year was last year when he was a beast offensively but lacked game to game consistency and was atrocious on defense. Had a ton to do with injuries because he started off the year absolutely beastly and was a ghost of himself after coming back from his concussion/ shoulder issue or whatever it was. Not to mention he had to carry Nylander also who couldn't hit a soccer net with a tennis ball from 5 feet out.