In the video it doesn't sound vague, it sounds very loud. My first reaction to the video was find the cause before any further driving. However, audio can be very misleading based on what was used to make the recording combined with what is used to listen to it.

Does it get worse at higher rpms?

How is the engine running--missing or loss of power?

Can you check for fault codes?

As I read your first post, the noise was not there before you worked on belts and pulleys
and you have replaced everything associated with the belts. In spite of and because of that, a guess would be a bad pulley, pulley out of alignment or loose belt or a belt that needs to be dressed. Usually those causes get louder at higher rpms though belts sometime quiet down.

One way to pin down where the noise is coming from listen to various parts of the engine with an auto stethoscope, a piece of hose or a ratchet extension.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas