I'm guessing VVT gears are the sound but the cause may be the solenoid itself or the wiring too it. I have seen that there are screens on the side of the engine. My thoughts are that oil is slowed getting to the gears and once the oil gets there the noise stops.
I have a 2019 Tacoma that has a very loud rattle with the truck first starts up in the morning. It lasts about 30 seconds then stops and runs fine. I took it back to the dealership and they replaced the VVT gears but it's still making the sound. Seems to be coming from the front top of the...