I have this issue with all Cubase compressors, idk what is going on in there. There’s some default gain compensation algorithm in there that is completely out of whack crazy. All compressors boost volume massively even with no compression occurring and output gain turned down by -12dB.
Here: no compression, output turned down by 12 dB, still getting ~6dB boost!
I don’t think you understood what the problem is. The problem is that voxcomp (and some others) boost the volume insane amount for no reason. So much that it makes it impossible to gain stage because the boost is 6+ dB higher than what the output knob allows to compensate for.
This is an abnormal, broken behavior I’ve never seen in any other compressor plugin.