I worked for AWS Premium Support over a decade ago. Waiting 3 days or more, for a non-premium support customer would have been not unusual back then either. But at least the quality of response was typically pretty good, haven't seen what it's like lately.

They've always struggled to hire for those roles. The people who are best at Engineering Support also tend to be the people who move on to other roles after a year or two.

Imo AWS support is pretty decent compared to other vendors. Azure was by far the worst I've ever dealt with--engineers becoming adversarial and passing blame in tickets without actually resolving anything.

I've had some run-ins with poor AWS support and have even gotten bill credits/refunds when they offered incorrect advice. It really depends on the service but in general they're fairly good.