Stems and background vocals

Hi there,

I have a weird question.
I’ve been using a web app to create stems of songs for use as accompaniment tracks (personal use only). In some cases the songs are in the wrong key, which means I have to adjust the pitch. I use audacity to make adjustments.

However, if the song has background vocals and I have to change the key by more than 3 notes, they sound “odd.” Is there anything I can do to adjust them, so they sound more “normal?”

EXAMPLE: I have a song with background vocals I had to change the key from Ab to F. (I know that’s a lot) the background vocals sound too bass-y. Is there a way to tweak them? Or am I out of luck?

thank you so much!