Sean McVay gave up Goff and a crap ton of draft picks for Stafford. If it wasn't evident before: QBing matters. Goff got swallowed up by the moment, gave in to the pressure, and made a bunch of terrible throws. No coach and no game plan can account for what your QB decides to do on the field.
Yes, Johnson called an absolutely terrible trick play that did major damage to the team, but Goff threw 4 picks, including a pick 6.
The only coaching mistake I saw was thinking that an all-out blitz attack was going to be viable against Daniels. It only worked against Darnold because he completely lost his ability to use his brain and throw the ball. Daniels showed how you make quick decisions, step up in the pocket, and throw available routes underneath.
Vikings need their Stafford/Allen/Daniels.