Sorry I meant pulley turn when belt isn’t on…
Here is a video to the sequel sounds a little more like metal maybe a bearing on the alternator pulley is gone as sound is from there.
https://streamable.com/h6n8a2
Suspecting the alternator pulley here is a pic, what tool is needed to replace local garage is saying £140 for doing just the pulley change.
About the grease thinking of taking the belts off and cleaning all the pulleys