Gnome is definitely keyboard driven, this is my workflow: Use Super + type name to launch apps, then tile them left and right with Super + Left and Super + Right. Two apps are enough for a workspace, if you need more, move to a new workspace using Super + Alt + Right. Gnome automatically creates new workspaces as you go, so you always have enough space. Swap between apps using Super + Tab. Almost like a tiling window manager, right?

The plugin system is indeed very good, extensions can do pretty much everything. They break on an update because it makes sense: The author designed the extension for a specific version of Gnome, and it can't be guaranteed that it still works as intended on a newer version. You surely don't want an outdated extension to really mess up your desktop when it hasn't been properly updated. This is the safe way.

And regarding customization? Funny story: when I started with Linux and I wasn't really into the meta yet, I started with KDE, but I switched to Gnome (GNOME 3.xx and GTK3) because I found it EASIER to customize. Gnome themes always looked way better than they looked on KDE and they were never bugged (e.g. missing contrast, wrong iconography). Also "extensions" were way less bugged than KDEs equivalent features. I only later found out that people preferred KDE because of its customization. However, I do agree that with Libadwaite, they really put an end to Gnome theming, but all in all, I think it's better because of app uniformity and an easier app development process (you can really see the Gnome app ecosystem flourish). Also, Adwaita looks pretty amazing nowadays, I don't really feel the urge to theme my desktop.