Well there’s a simple thing you are overlooking. You could just not theme Kde with third party themes and extentions and stuff like kvantum themes. It wouldn’t break, just like gnome. Still if you do decide to change stuff its going to be fine most of the time. The beauty of Kde is that there is the option to change stuff, but you aren’t required to.
KDEs default layout is really beautiful and well put together, just like gnome is.
Oh and don’t forget to take backups of your /home. Thats good practice for every desktop environment.
KDE doesn’t even need me to use plugins to break though. Just messing with the themes that are delivered with KDE by default is enough to break it.
That really shouldn’t be happening, make sure to file a bug report if it’s the core themes!
Hasn’t happened to me in the years i have used KDE.
Which theme and what did you do? I’ve never seen breeze break.
The last time I broke Plasma with themes, was because they weren’t compatible anymore. They could do better with the store, though, there is a lot of stuff which doesn’t work anymore.