I agree, variable output is a good feature for an mx110z like you and I have.
Don’t forget, you have individual level controls on the top of the mx110z for your AUX and Phono 1 and 2 so you can match the input volume of those inputs. You can find a combo that works well without sacrificing that feature.
As a test, main system, I ran my Laptop’s headphone out to mx110z’s AUX. Worked, nothing special. Upstairs, Office PC, I just changed from headphone out to a USB out to DAC, Topping D10s, made an OBVIOUS improvement in SQ, as well as much more volume.
Just to hear it, I’m gonna try using my Laptop’s usb to topping in the main system.