What makes Linux appealing to me is the extent of customizability, but I didn’t find many answers when looking up with desktop environment is them most customizable. Some say KDE is most customizable than say, Gnome, but doesn’t Gnome support CSS customization while KDE doesn’t?
Everything is customizable if you are brave enough with the code :)
But yeah gnome is known for breaking changes & rewrites. As a result, Cosmic desktop was born to be more stable and reliable with plugins. That’s ~alpha. But if you truly wanna DIY, then the tiling window managers are king. Stuff like dwm and awesomewm where you configure every part of the UI and can easily make your own widgets