I'm quickly learning that these things are rattle traps, so i feel like its a bit futile hunting down every single rattle, but this one was obvious, and more importantly, i could isolate it. When i pushed on the trim around the gauges, the rattle / buzz stopped.
So I decided to try to stop it. The trim just pulls off, tilt the wheel down, grab in two good places and pull. I couldn't find anything obvious, so I spent a bit and put black silicone around all edges i thought were contacting, and wrapped a bit of electrical tape around the clips. Let it dry overnight so i wasn't gluing the thing in, and shoved it back in this morning.
It worked! I'm not really sure what was rattling, and i actually think the metal chrome piece on the outside still rattles, and the entire car generally still sounds like its going to self destruct, but I got the majority of the pinpoint-able rattles from this spot by doing this.