I edited the box to include more text and the image didn’t seem to get any larger. Are they showing larger for you @martinsauter than they are for me?
A tiny logo [as in just large enough to identify the plugin leaving the message, but not so large that it’s obtrusive] is a good idea.
I have logged into client sites that had 5+ notifications and one of them was important and from LiteSpeed but I did not know that as it didn’t identify itself and the error was a bit obscure.
These do look reasonable to me: http://www.screen-shot.net/2022-11-01_14-24-21.png
It may be that they scale larger if the message is not a single line?
You gave feedback, and they listened to what you had to say. Not agreeing with your opinion isn’t hubris, it’s a difference of opinion.
Ultimately if they choose not to act on the feedback you give that’s on them.