UPDATE:
read this first. You CAN route to Background Rack
Audio doesnât route to the background rack.
Its output also doesnât route to other racks, as far as I can see.
Try creating an output rack that you include in all your songs.
The fader stays where you last left it.
You can include any other âmasteringâ effects you like in there - such as compression or eq.
It works perfectly well.
Looks like youâve already been into this here, but I think Brad is recommending making your own top level racks.