Scenario: I put a song I wanna learn on guitar (wav file) into it. I slowed the tempo down to around -60. But I’m getting this annoying electronic, reverby distortion.
Any way to clean or fix that?
Thanks! 
No, I don’t think so. It’s just a side effect that you get when you change the tempo a lot.
An alternative, which may not be much help, would be to “Change Speed” to half speed - this will slow it down a lot and drop the pitch by exactly one octave. I don’t know if you will find that more or less annoying.
For Windows or Mac, there is an old application called “Musicians CD Player” which may do a better job than Audacity.