I did a piece a while back on Kirk Cousins that looked at all his stats and how his game will fit with Kubiak’s offense. Part of that piece discussed Cousins’ reputation for coming up short in big games, and against winning teams.
Recently Brett Kollmann put together a very extensive video of Cousins’ performance against winning teams games last season- showing Cousins was not to blame in all but (perhaps) one of those games.
This video goes a long way in dispelling the notion that Cousins was to blame for the Vikings losses to winning opponents last year, and includes a lot of detail.