It's weird that one of the reasons that you endorse AWS is that you had regular meetings with your account manager but then you regret premium support which is the whole reason you had regular meetings with your account manager.
If you know what you're doing you don't need AWS support. We add support when we want to do something new, like MediaTailor + SSAI. At that point we're exploring and trying to get our heads around how things work. Once it works there's no real point in support. That said, you need to ask your account manager about (1) discounts in exchange for spend commitments, and (2) technical assistance. In general we have a talk…
Depending what precisely you mean by the second one, you may not even need an AM/support for that.
They won't help me use the platform, but they will still address issues with the platform. If you run into bugs, things not behaving how they're documented, or something that simply isn't exposed/available to customers they seem to be pretty good about getting it resolved regardless of your spend or support level.
(On my personal account with minimal spend, no AM, and no support... I've had engineers from the relevant teams email me directly after submitting a ticket for issues.)
So yeah, "if you know what you're doing" you probably don't even need the paid-for support.