Trying to figure out what the broken tube is under my car

Hello,

Is the tube towards the front or back of the vehicle?

If you would please upload a few pictures of the tube. This will help us determine what it is.

Let me know of any questions.
Thank you.

I tried to put the image in the original post, guess it didn't work. Someone told me it could be for the A/C excess water, but it feels weird to see it going so low and I wonder if that could cause the rattle.

It is a drainage tube for condensation. So, this is a completely normal setup for your vehicle.
As for the rattle this is not likely creating it, as this is a rubber tube.

When do you typically hear the rattle? Is it when you drive/ go over bumps or as soon as the engine is started?

Rattles can come from any of the splash or exhaust shields that are under the vehicle. You can try tapping on those silver shields around the exhaust tube and see if you are able to recreate the noise.

The rattle is directly linked to the speed I'm going (the faster I go, the faster the sound). It's not always there, but often. I'd say that it is more when I accelerate. The car is almost new (1 year old), but I'll check the shields to see. And so far, I always drive fully electric when I hear the sound.

Let me know what you find as far as the shields are concerned.
Also, since this vehicle is under warranty you will be able to take it to your local dealer for a diagnostic.