Hi-- I'm also interested in poetics and had been looking at the SUNY buffalo program earlier this season. The impression I got of it from my professors, faculty/student profiles, and course offerings was that it was indeed largely geared towards the study of the poetics of modern/ contemporary/ avant-garde poetry. It also caters to students who are both poets and scholars of poetry-- so there's a creative component to the program (also because poets like Robert Creeley/ Charles Bernstein founded it, etc). An interesting program, but its niche was not my thing, and tbh it doesn't sound like it's yours.
I don't think you have your definition of poetics wrong at all; we talk all the time about the "poetics of the novel," etc. I do doubt that any program is geared towards the study of "poetics" as a whole, not applied to poetry, because that would be too broad and undefined to be a distinct focus.
From my limited, meager perspective, just based off the little I know and what you wrote, it does sound like the program wasn't right for you, and you'd probably be happier elsewhere. Maybe look into theory-heavy programs like Johns Hopkins Humanities Center? Or take a look at grad student profiles at different places and see if any seem parallel or analogous to your interests? Good luck!