[jeroenhd]

Gnome and GTK are heavily opinionated towards client side decorations. That means the fat borders are part of the application, not necessarily of the desktop manager.

You can make your own themes pretty easily though, if you want to change the theme. There's some quite-good-but-not-quite-there macOS themes that aren't too bad, especially with the top menu bars that Ubuntu used to have.

[kasabali]

Client side decorations doesn't necessitate having gigantic buttons with swath of padding.

[jeroenhd]

You're right, but in practice this means that the gigantic buttons are part of the application, not part of the desktop manager itself. Even if Gnome 40 tried to remove the touch-friendly buttons, it'd be up to the applications themselves to actually make the interface work like that.

The buttons and styles are a choice by the developers of the applications. Often, they follow the Gnome design language (which is good, because that's how most of the Gnome ecosystem delivers a unified experience), but very often they also make their own decisions about where the buttons go and what size they are. It's possible to change a lot of this with custom themes, but changing the size of components often breaks applications or layout because the developer did not intend the size to be changed.

I personally enjoy the look and feel of Gnome and I don't have any problems with the UI, but in the end my experience is dictated by the people behind the application. There are plenty of application on my system that don't follow the design language of my desktop environment, and if the Gnome design team redesigns their preferred UI, applications will have a mishmash of styles for at least a few years until things have stabilized.

Had the decorations been server side, then all that needed to happen was a quick change to the theme and maybe to the rendering components and the theme would've switched.