Probably doesn't apply to you, as my mac is an ancient Mojave intel powerbook but had exactly the same problem for years, so it could be some kind of audio driver issue which will never be fixed. Game ran great, even 'acceptable' with new shaders enabled, but audio constantly stuttering, from title music and cut scenes to in-game effects. I was heart-broken until I just gave up and installed the og Neverwinter Nights Diamond edition through Wine and never looked back. Everything runs perfectly now, butter-smooth even through emulation! Thanks for nothing Beamdog.

The only problem I had was voices being muffled but it was fixed some months ago. After that, no issue whatsoever (M1 Macbook Air).