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.