Rattle sound

This could be a number of things but could you get a recording of the noise so that we can get on the same page?

If this is only making the noise when you are pressing the accelerator at lower speeds, I suspect this is detonation. In other words it is spark knock. This is unburned fuel that is igniting at the wrong times.

If this is the case, the knock sensor should pick this up and adjust the timing or fuel so that it does not happen.

https://www.2carpros.com/articles/how-a-knock-sensor-works

However, if you have bad fuel then it may not be able to adjust enough.

Let's get a recording of this so we can e sure this is what it is. Thanks

Sorry but I am not picking out the noise. Does it make it at any specific time in the video?

Got it. Can you duplicate this by sitting still with the vehicle in park and just revving the engine?

That does sound a bit like an upper end rattle. Clearly it is muffled but that would fit with when you are hearing it.

However, if this is an upper end noise like a valve train noise, then you should be able to lift the hood and have someone rev the engine and pick it up.

Have you noticed this getting worse? Is it a chance that this is normal? Have you owned this since new or did you just buy it?

What I would suggest is going to a dealer and asking to compare this to another vehicle with the same engine and transmission.

It almost sounds like exhaust rattle from a hanger or pipe barely touching as the engine flexes. Similar to a heat shield that is loose on the body of the car.
Try this, pull up to a solid wall on the drivers side. Stop the car, put it in drive and hold the brake down, now rev the engine and see if you can make it create the noise and record that if it does it. Try the passenger side as well. Being this is a turbocharged car it could also be an issue with a turbine wheel bearing starting to fail under load.

I agree with Steve that more than likely if it is not normal it is a turbo bearing beginning to fail. That makes sense with the idea that it does not do it on light acceleration because the turbo is not being spooled up on light acceleration.

Again, I am not convinced this is normal but I am also not sure that it isn't.

Not easily as it's inside the turbocharger. What you might want to do is take it to a different shop that didn't sell you the car and have them at least listen to it in person. They might give you an answer other than "It's normal" as they wouldn't worry about the warranty aspect of the repair like the dealership would.