it appears i’m having the same problem as this thread.
tho it doesn’t look like it was resolved.
suggestions were, try other usbc charger, grounded usbc charger. i’ve done two ones worse than the other. one is definitely grounded. the other that is worse is a battery bank. so could be noisier.
however another user suggests that shouldn’t be a problem.
and suggests reseating the trackpad… so i’ll probably open it up and do that next.