Audacity is as easy to use as any complex software can be with JAWS. It seems to be the audio editor of choice for many screen reader users.
And, yes, there is a built-in filter that allows you to slow down music without the pitch changing. I had to do that for someone I was helping to put together the music and other audio for a dressage routine.
Brian - Windows 10 Home, 64-Bit, Version 1803, Build 17134
A great deal of intelligence can be invested in ignorance when the need for illusion is deep.
~ Saul Bellow, To Jerusalem and Back