KDE's telemetry is opt-in. It does no telemetry by default. Why is that a concern? If you don't like it, don't turn it on?
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.