this maybe but I can´t hear any other beats. The metronome plus the count-in routes through the drum track. So I can mute all other tracks but still any drum used is louder than the 2/3/4-beats.
The midi-volume in the count-in dialogue doesn't work neither, you can only choose the instrument but this only affects the count-in, not the metronome during playback.

The forums are full of "how to make the metronome louder", so I capitulate.

This is really a mess. I just tested an old BiaB from 2006: it's all exactly the same there. This problem is 20 years old. Shame on pgmusic.