The problem is that any design fresh graduate would NOT design it that way. Don’t get me wrong, KDE is a great DE in terms of performance and general philosophy however it fails hard when it comes to simple design principles.
For eg. icons bellow “places” aren’t properly sized to the text, they’re abnormally large. The labels itself lack proper vertical and horizontal padding. Everything is simply crammed against everything else without the right space in between. This is also noticeable in the program icon on the top left.
If you compare the image above to both Windows and macOS you’ll see they spend a lot of time making those things right and that gives you a cohesive and polished visual experience not what KDE has now. Even xfce which doesn’t care much about visuals is doing better on those.