UI matters for a vast majority of users and use-cases, I can live comfortably with tiling windows manager, but this is not the expected default.
That's why I stayed on Catalina for a long time, Apple has lost the focus from the past (and must reread some old HIG documentation for a change). Beauty is not a function of usability (example: the new Safari), the process of making interfaces more "exciting" and "fashionable" has his roots in marketing, not in product design.
I have tried in recent months all forms of DE's for Linux, the simplicity of Cinnamon and Mate was appealing but somewhat limiting.
KDE is modern and extendable, there are a ton of native apps and the experience of customizing the UI is more coherent and logical.
The only gripe that I have with KDE is the built-in telemetry, but luckily PureOS KDE is older implementation, so for now I am ok.:)
I am newbie in this world (from a desktop perspective), I guess I consumed more GNU philosophy in latest months.:)
May be I have unreasonable expectations, but you are right, the telemetry is opt in.
But don't worry. KDE as as free as it gets.
Gnome UI looks childish and overblown to me.
As an UI designer I can confirm that in recent years the trends to maximize engagement trough overuse of animation and unusable distractions is making me mad as hell. The useful and really effective design is invisible.
Or as the new generations of "tech founders" classify polished professional UI work - it is "not exciting enough". I have a different view on interfaces: Never use form over function methodology, the main goal of interfaces are to be useful and accessible.