So a stereo tracks pitched won’t sound good
Let’s think about the track as oppose to a live band
If the singer wants to change the key
The drummer and percussion don’t change pitch
Instruments do
So best cleanest option is to purchase Multitracks from Karaoke-Version not stereo tracks
Download each stem by soloing each and download each one
Import into a DAW
I’d recommend Waves Soundshifter plugin for pitch shifting
and if say you need -2 semitones change
You put an instance of Soundshifter on each stem except drums and percussion
Export your audio either as a stereo track or multitrack for Stage Traxx