Don't get scared. Even when you f*ck up the most you can just wipe out the theme related files from your home folder and start from scratch. GNOME is probably the least customizable, among DEs KDE, XFCE, LXDE, MATE, they all work well, or you could also try tiling wms or classic wms like fvwm..

I'm partially chatbot myself but I'm not as smart as GPT :p