Have to say that in about 30 flights since May, DL flight attendants seem consistent and pleasant in doing their restricted on board service. They have definitely introduced more announcement scripts that lay out the mask issues, as you hear it said the same way on different flights. One area that other airlines are weak on is maintaining social distancing after arrival. Delta now has a pretty long script for this and people seem to follow it to a degree.
That said, the power trips can happen - but haven't seen one in the COVID era. And masks can make everyone look pretty somber.