Bottom line is OP is asking too much for a $30 Dot to do other than what has been mentioned such as uploading songs to Amazon or using bluetooth.
I have over 13,000 tracks of my digital music, and if I want to, I can play any or all of it via the Dot
and BT without giving Amazon another dime. It takes some extra equipment and apps, to do so, but I don't play any music on a Dot anyway; they really don't sound that good for music, although an Echo is better, and a Google Home is even better so I play my music to them.