Adjusting Keynote video volume and GarageBand music levels

Is there a way to turn the volume up on videos in Keynote while making the rest of the music for the presentation quieter? I have made a Keynote presentation, and I'm playing a song edited and timed on GarageBand to go silent during videos in the Keynote presentation so you can hear the videos, but the videos are too quiet. The quieter I record GarageBand, the quieter the inserted videos become. Since the song plays across all slides, changing the volume on one slide changes it on all slides.

I'm new to GarageBand and adding music to Keynote, so keep it simple and include all steps from the starting point, please. (If I insert the song individually in each of the many slides, will it start over on each slide? I didn't think so, since that's the function of playing across all slides...)

I'm working on a MacBook Pro (2021), iOS Tahoe 26.7.