You need to increase PWM freq, fast/phase-correct doesn’t really matter. IIRC comfy has now tested different frequencies and fast/phase-correct on several or all of the BLF/Oshpark DD drivers. They all operate.
I found HarleyQuin’s post here helpful on the topic of PWM freq. You want 19kHz PWM to minimize whine. Do you know what frequency PWM you are using currently? If not post what specific firmware you are running and what you use to flash it (such as the batch file you use or the string you use to call avrdude).
Good looking project so far!