The way that you've explained your reasons for hating the design so much, I think it absolutely does sound egotistical. You don't like it just because it goes a

The way that you've explained your reasons for hating the design so much, I think it absolutely does sound egotistical. You don't like it just because it goes against your arbitrary personal preferences, even though the company paid outside specialists to come up with the design and nobody else sees a problem. You're asking to throw out some of the progress that has been made just for your own pleasure. Maybe there's a better way to explain what's wrong with the design. Don't just say "I hate it because my ADHD and that's it," explain how the design makes the product worse (if it actually does) or what is wrong with it. I don't understand how there could even be a shape so ugly that it's worth throwing a fit over. Even if it was something really stupid like a calculator app where all the buttons were shaped like starfish, couldn't you just suck it up and make an ugly UI?