I'm merely sticking with your definition of "stuck with" to keep the terms of the conversation consistent.
You said it would be a coach who considered Goff as merely "serviceable" with great coaching. If that's what Goff is or what a prospective head coach perceived him to be, then that head coach would surely be stuck with Goff. Any head coach we'd want, which would be one with a greater than average IQ, would understand that there is no way in H-E-double hockey sticks he's going to be able to summarily dump the guy the team just sold the farm for and drafted first overall like Carroll had the luxury of doing with Matt Flynn after drafting a better QB in the 3rd round. He's going to know two obvious things. One, it will immediately set him against ownership and; two, he can't count on the low probability of finding a franchise QB in the 3rd or 4th round enough to make being stuck with Goff a non-issue.
All of this is really neither hear nor there, though. The Rams (Demoff/Kroenke) won't hire a new head coach that won't commit to Goff in interviews and, as I already said, whoever that ends up being will say publicly Goff is the reason he wanted the job, whether he truly believes it or not. Any serious candidate who isn't thrilled with the prospect of being stuck with Goff and is honest about it won't be a serious candidate for long. Goff is the guy ownership wants being the face of the franchise and anybody not willing to play along won't get close to the job. This process is first and foremost about Goff and only secondarily about finding a great head coach.