This should be a setting under “Cast Options” in Google Play Services options. At least that’s where that generic notification is on my Pixel.
Won’t affect your “direct” casting, like Spotify, just the generic broadcast, without turning off the per device options.
I’ve turned off the broadcast on every device in my world, because I found it obnoxious.
TL;DR: Samsung is better, according to the author.
Some questions remain though, as Google’s Magic Eraser gives multiple options for object removal. Some are quite bad or blotchy, others are nearly seamless. Don’t like any of the options it’s provided, then ask it to try again. The author doesn’t touch on this at all. Did they select the first option everytime? Was this the best of the options they were provided?