hmmm well that may be good news then. The sound definitely remains when stationary.
Possibly good possibly not.
Don’t get too caught up on “where” the sound is. It’s part of it, but crazy enough sounds can seem one place and caused from another.
The earlier answer is correct, if you are in N, and rev the engine, and the sound increases and it speeds up, then it’s (most likely) somewhere engine related or parts bolted on the engine.
I would open the hood with it running and have someone Rev it, see if there is a culprit. I trend to go easy checks first.
1. Make sure you have enough oil, ha.
2. Pulleys, metal grinding do any of the pulleys touching the serpentine belt throw obvious sound.
I’ve chased a squeak in the belt, a mechanics stethoscope can help, it a long screw driver touching components and next to your ear is old school.
The pulleys are usually fairly easy to change.