I've been back and forth with multiple managers and C levels that any metric chosen can and will be gamed. But they again and again want some quality assessment to use.
For a while, they used tickets closed. So we all started submitting BS tickets to do tasks like "send email". You all can imagine the inanity of that.
From my experiences there is no good way to track... Well, perhaps having a grab bag of conflicting performance metrics, and then choosing one at random? (But again, even that can be gamed)