I am currently in a support role at a company(not GCP) with some pretty big enterprise customers and let me just say that supporting software is fucking hard.
You essentially have to be a systems engineer/sysadmin for every one of your customers with only as much context as your customer is willing to share.
You are 100% right, but it's worth noting that this is why there's a whole model of b2b interaction that involves embedded engineers partnering with a company to solve their specific problems (IBM, SAP, etc.).
The reason Google support has a hard time of it is Google doesn't offer that model to all its customers, just the ones that can pay a lot of money. But support still has the job of helping everyone else (with all the challenges you've described that such entails).
I think most of the annoyance with Google is their culturally not seeming to understand that model even exists.
Their zeitgeist appears to be "Other companies needed to provide that because their technology was wrong / incomplete. We'll just build things right instead."
Which is batshit insane, in the same way that expecting a veterinary pharmacist could prescribe for humans... with better technology.
You essentially have to be a systems engineer/sysadmin for every one of your customers with only as much context as your customer is willing to share.
I like my job, but please have mercy on support.