I think this is true to an extent, he's not Burrow, Allen, etc., who can sometimes elevate their teams all on their own, although if Lamb just catches 1-2 of the three second half drops you could easily say Dak won us the game with big plays down the stretch.
They weren't just three random drops at random points in the game, one was a huge 3rd down conversion late in the 3rd (or even early 4th) that would've given us a 1st down around the Eagles 35, instead we were punting. The other would've given us a 1st down around the Eagles 20 with 2 minutes left.
Better QB's are better for a reason, but they aren't supermen who consistently win games despite their teams fuck ups. Lamar Jackson in particular couldn't drag Baltimore to playoff wins the last two years due to team fuckups, along with a few of his own.