I have the same issue as so many others on Reddit and 9to5 Mac forums.
Apple replaced my MBP and a few days after a clean install the issue started again. The crackling sound can also be heard using headphones so it's not a hardware issue.
One theory is that legacy code running in 'Intel' mode is responsible for these glitches. see attached sample.
It looks like a compatibility issue with certain Intel based code running on these M chips. I have the same setup on 2 other Intel MBP and never experiences these issues.
Try closing Intel running processes from the 'Activity Monitor' app and see if that resolves the issue. For me it seems to be reduces but still 'cracks' from time to time.