Let’s be frank, quarterback wins are not a legitimate stat to begin with. In order for a quarterback to be credited for a win all that is required is to have started the game and for their team to win the matchup, thats it. A quarterback can be benched for poor play halfway through a game or injured on the first play and STILL get a win put on their résumé. For example, Trey Lance left the 49ers’ week 2 win with a broken ankle. Despite only throwing 3 passes and Jimmy Garropolo finishing the game Lance was still credited with a win for starting the game despite contributing next to nothing.
Wins also do not indicate if the quarterback actually played well; a Qb who throws zero touchdowns and multiple interceptions will still earn a win if his team is able to overcome his miscues. Despite Justin Fields not contributing a single touchdown and throwing two interceptions his team still won without any significant contribution from their starting signal caller.
With this in mind looking at wins against winning teams further skews reality. Josh Allen, Kyler Murray, Joe Burrow, and Justin Herbert are widely considered the best young quarterbacks in the NFL, however all have losing records against winning teams and only Josh Allen has an overall winning record as a starter.
Furthermore, despite being hall of fame worthy players, both Drew Brees and Aaron Rodgers have losing records against teams that finished the season over .500. Having a winning record against winning teams is actually the outlier; Tom Brady and Russell Wilson are the only active QBs who have played at least 30 winning teams in their careers and have a winning record. Using this narrative to judge a quarterback’s worth would disqualify most of the league from being considered good players. To many factors go into winning a game to put to much credit or blame on the backs of quarterbacks and if you want to use wins against winning teams as a metric you’ll be sadly disappointed by the outcome.