There’s more you can read above if you scroll up.
I can say with high confidence based on the prior posts and evidence presented that there is nothing wrong with the record levels on the Prime 4, and the digital gain structure and digital recording appears to entirely conform to usual digital audio standards.
Put the master volume control at its ‘unity’ zero mark. Putting it higher will compel running the channel trim-gain knobs too low. Putting it lower will compel running the channel trim-gain knobs too high. Putting the master volume control at its unity will also show you the exact levels the recording will be at on the master meter.
Adjust the channel trim-gain knobs for each track to achieve whatever volume is necessary so that the densest, most complex music (or noise) peaks at the 0dBVU nominal level point on the channel meters. The most dynamic and sparse music should peak higher than this but definitely not go into the top meter LEDs (Overload/Clip), preferably also trying to keep out of the second-to-top LED that you treat as safety headroom for accidents.
Unity on the faders is max. When a song is playing out by itself, the fader needs to be all the way up to send the full volume to the master. Also be aware of the consequences of crossfader curve and use of effects on master volume.
If you want your internal Prime 4 wav recording louder than where it’s going to end up, with many of the peaks when the music was in full swing ranging from about just above -8dB below clip to -18dB below clip, assuming you tried to stay out of those second-to-top LEDs, then you take your recording and adjust its volume later in a sound editor or DAW program in the post stage. Here you can also EQ it, trim it, etc, too.