First, any thought that Matt Stafford is going to flop borders on tin foil hat stuff. The guy can spin the ball, read D's with the best of them, and has amassed huge yards and stats for 12 years.
Second, if the logic is that it takes time for Stafford to absorb and operate the offense, then of course there is a honeymoon period to allow for this. Although I don't think it will play a very big factor.
Third, if the idea is that unless the Rams go to the Superbowl Stafford has failed is not realistic. No one is claiming that Stafford is Brady or Montana or even Aaron Rogers. A lot has to go right for a team to make the Superbowl and injuries that are entirely unpredictable has a huge effect. Teams that usually go to the Superbowl and win have had few injuries to key players.
The "hot seat" he is on is yours and maybe some other Rams' fans. But he's not on the organizational hot seat in 2021 at least.