If you guys want to pitch shift / change keys with your music subscription account (e.g. Apple Music, Spotify) you can with the “Djay” app in iOS mobile. You don't even need
Transpose △▽ pitch ▹ speed ▹ loop for videos
Music Speed Changer iPhone, iOS Tempo App & Pitch Changer Apple MP3
Change the tempo and key of any music! | Pitch Switch by Inspyder