iPhone 12 mini audio issue. Possible manufacturing defect
Crackling sound from both the speakers.
Bluetooth earphones work.
Sometimes audio works, sometimes there is crackling noise, sometimes no audio
Found an article that this is a know manufacturing issue in iPhone 12 and 12 pro.
iPhone 12 and iPhone 12 Pro Service Program for No Sound Issues - Apple Support
Nothing for iPhone 12 mini, but it’s this same issue.
iPhone 12 mini