I'd say that this isn't an "overhaul", they didn't redesign everything just to make it different, they refined and optimized pretty much every part of the DE to

I'd say that this isn't an "overhaul", they didn't redesign everything just to make it different, they refined and optimized pretty much every part of the DE to make it more power efficient (QT6, KRunner), more visually pleasing and consistent (Breeze theme), more featureful (HDR support), and of course more stable (countless bug fixes)