To make this clear: I’m talking about the app icon on the left side of the notification, not the image/icon you can put on the right side.
I’m a minimalist and would prefer if those notifications only had one icon, which I specifically chose for them and not the Home Assistant logo on top of it.
Yes add the key notification_icon: to the data section of the notification.
Nice. Contrary to what I expected, it even changes the app’s icon within the notification panel. Unfortunately the icon always has the Home Assistant app icon’s blue color, so it won’t be that easy for me to discern between different icons from a glance on my stationary, always wall-charged Pixel 3, considering how relatively small notification icons are on Android 12.
By the way, why did they not implement this feature on iOS? Other apps change their notification icon depending on the context too on that platform.
Just add color: "purple" (pick whatever colour you want) under the data section.