[Dave in MN]

Have you tried to duplicate the sound while in neutral with the tires blocked by slowly raising the rpms? If you have someone in the car slowly raising the rpm until the sound presents itself, with the hood open, see if the sound is louder on one side vs the other.
If you cannot duplicate the noise while "freewheeling" in neutral, the noise may be coming from the drivetrain behind the engine.
If you can hear the noise while parked, take your fan belt off to see if it is still present.
Please try this and get back to us.

Poking fun at myself: I once had a severe main bearing knock until I removed the fan belt! Oops!
Good Day!