Get rid of the Scarlett and get a proper USB DAC like a RME ADI2.
Someone asked you to name your speakers and you didn’t tell. Is this a secret?
Without more info like speakers and pics of your room it is all guesswork and a waste of everyone’s time.
If the boombox sounds better, there are much greater problems here than the Yamaha. The Yamaha is showing you the problems elsewhere.