That’s not a valid comparison at all, and it’s not pedantic to point that out no matter how preemptively you claim that it is.

Bilapial ≠ lapiodental! It’s not that hard to understand.

The entire similarity between K and the German Ch is based on them both being velar (and unvoiced). You’re crafting a strawman by focusing on the “fricative and plosive” manner while ignoring that the sound is made at the same place.

S and T are almost a better comparison because they’re both technically alveolar, but that ignores the fact that S has a dental component. Try making a T sound and then an S sound without moving your teeth. It won’t work.