So maybe he's just someone who, the worse things get, the worse he gets?

I could see that. He's someone who wants to be on the winning side no matter what, but if things are generally good "winning" is probably just a matter of everyday domestic politics and not world-changing disasters. The lower the stakes, the less likely he's going to end up causing awful things by trying to make sure he's betting on the right horse.

I'm guessing the Regent is more or less the boss of Dixing, while the Envoy/Ambassador has jurisdiction over Dixing stuff in Haixing

The Envoy also seems to have a say in how crime is punished, to some degree, but otherwise, yes, I'd agree.