The light flickering on stars and planets has to do with the Earth’s atmosphere. In a dark sky look straight up and the stars directly above you will blink much less, and as you look at stars closer and closer to the horizon, they start to blink more and more. The worse your overall seeing conditions are for the night, the more intense the blinking can get.
Huh, I’m pretty sure neowise had a lower magnitude. I was in a city at the time and could see it through the light pollution at night with the naked eye. This one disappears quickly in the dark after the sunset goes towards astronomical dusk… And the moon light is also making it impossible to see. Maybe looks brighter at sunset in specific parts of the world, but at least my experience in its glory was nothing like Neowise.
Also earthsky claims magnitude -5 to -7. I don’t believe that. For context, the magnitude of Venus is about -4 and that planet outshined the comet greatly.