The noise could be due to a myriad of reasons. In my youth we would install a 10A noise suppressor in line with the power source close to the affected device. These filters are still available and cheap ($10-15).
https://www.jaycar.com.au/10a-dc-noise-filter-improved/p/AA3074
For more information on the subject I found this. I read most of it and it's bettr than I could do to explain the issue.
https://www.crutchfield.com/S-JY9PcbDJHR2/learn/learningcenter/car/noise_suppressors_installation_guide.html
I hope this helps you solve the alternator whine you're experiencing.