I bring up the 49ers game/S as they are just about as Clutch as you can get, now there may be contributory reasons/excuses as to the failures, but it could also be attributed to a lack of composure in the more pressurized scenario's.
Indeed, rather that move on from Dak's 55 Rating when Trailing <2mins, you could extend it to add Trailing with <4mns, where his 73 Rating lags way behind: Allen, Cousins, Stafford (and even trails Goff).
Another example of less than Clutch performance is the number of 4th Q comebacks which have dramatically reduced since coming back from the 2020 injury. Indeed, when requiring a TD he's only managed one comeback and that was against the 1-11 Texans. Yes he's had 4 comeback wins in that period, but the other three he had the cushion of just requiring a fg.....again that lessen's the pressure and so diminishes 'clutchness'
Interestingly, he has a tendency (over the past two seasons) to be unable to pull out those comebacks where he's playing a good team and despite having the ball eg Buccs in 2021 and the Chiefs where after going down by 2 scores but Dak had the ball on 9 occasions and was unable to dent the lead.
Again, im just of the opinion that Dak's the very QB you want to protect a lead, but not when he's chasing and pressure mounts.