@moonlight Just following up here. I got in touch with a Seeed Studio representative offline, and I got an answer. Unfortunately, it’s kind of vague: “There is an issue that has cropped up with the new Raspbian 5.5 release. We need to wait for a while for the 5.5 kernel to be stable and then we will solve the issues of the driver.”
I was advised to pursue newer HW models: the ReSpeaker Core v2.0 and ReSpeaker Mic Array v2.0. I’m going to give those a try. Best of luck.