Hi you,
in former Cubase Versions there was no control room - Long ago. It was then that we could adjust click volume I think in the Metronome dialogue. I suspect that this Parameter is still there and thus controlleable via Remote Controllers, but NOT available on any user Interface element of cubase.
The preferreable solution would of course be to have the click volumes for cues, etc. available for remote control as well. The decision on “what is controleable and what not” is a Little bit random since a Long time.
Cheers, Ernst