Persistent audio distortion on MacBook Pro — not related to headphones

Hello,

I’m experiencing consistent audio crackling and distortion on my MacBook Pro, especially during fade-out sections of songs (e.g., Apple Music). Initially, I suspected my AirPods Max, but after testing other output sources, I confirmed:

The issue occurs only on the Mac

AirPods Max sound perfect on iPhone

The distortion is also present when AirPods are disconnected, via built-in speakers

Audio is sometimes played at 24 000 Hz / 1 ch, indicating use of SCO codec

I have already tried:

Closing all apps that may access the mic (Viber, Discord, Chrome, etc.)

Switching input to “Internal Microphone”

Restarting coreaudiod

Fully restarting the Mac

Disabling all audio effects (Spatial Audio, Dolby Atmos, EQ)

Testing with a new macOS user account

Despite all efforts, the issue persists. I would appreciate support on:

Forcing macOS to consistently use the AAC codec

Reinstalling audio drivers without formatting the whole system

Known issues in macOS or T2 chip related to CoreAudio that might cause this

Thank you in advance.