Have you measured how much energy it uses once you have your frigate continuously recording and go2rtc multiplexing all the streams

I don't use it for that. I just put the option there for the context of the thread.

In my setup, Frigate runs on some 6th gen Intel desktop chip with a coral accelerator that regularly dies, however, on this old mainboard, it does not take the whole USB controller with it (contrary to the 9th gen intel host I've used previously).

I couldn't tell you how much of that system's power draw is frigate as it does a lot of stuff beyond just that.