When I was in the GNOME bubble, I too thought GNOME was the be-all and end-all of Linux DE usability, with everyone else being savages slapping together UIs without so much as a style guide. Perhaps at some point this may have been partially true.

Today, all major DEs are fine. Plasma did not crash once since 2019 for me and I think its UX is quite nice, in the case of Dolphin in particular visibly better than GNOME's. At the same time, GNOME had routine issues with extensions, semi-frequent crashes, and odd non-compliant bits like refusing to use tray icons, breaking apps that depend on them, and the last time I checked, scaling was a mess.

I do think the GNOME/libadwaita ecosystem is a fantastic achievement and agree with many of their ideas, but it would be dishonest to say all other DEs are inferior and don't deserve any consideration as a default.