Not stock,
265/75/16 wildpeaks
King 2.5 front and rear
This truck was new when purchased
Replaced brakes 5k miles ago.
That would make sense as the noise is related to braking and weight shifting.
Check all of the suspension connections and bushings for torque and lubrication.
Check the brake components for proper fit and wear.
The noise sounded like a "pop".
Which could be a dry (not lubed) contact point.
Or could be a worn contact point allowing movement.
Try rolling backwards and applying the brakes as you did moving forward to make the noise appear and see if the noise appears or changes.
This may help to narrow it down. You will need someone to listen outside the vehicle.
This might be a hard one to find until it visibly becomes apparent by shifting parts showing wear.
Two things are sure to happen, it will get louder, or you will notice a change in when the sound appears.
It may simple, check be the brakes,.... the disc and caliper contact point may be sliding, or the caliper housing has become loose.
Try this, with the brakes depressed, try to force the truck to move forward and then backward to make the sound appear.
If it does.
Someone outside the vehicle may be able to narrow the sound location down to a point of origin.
