Hello and welcome to the forums! Congrats on your new car purchase. I understand rattle noises can be irritating especially if it’s something obvious. I’m a Honda technician and get a lot of these come in the shop. If you look under the passenger side under the glove box and to the left, you can see your HVAC housing to your left. Try hitting the bottom of the housing with a closed fist with car off and if you hear a distinct rattle coming from your housing, I would bring it to the dealer and let them k ow you have a rattle coming from under the glove box. We have been changing out HVAC housings for those. If it doesn’t rattle I’d still suggest you bring it in. Many times I have found a bracket loose. As far as your civic, there was a bulletin to address the rear deck rattling. We would remove and apply EPT on the bottom to keep the deck lid from making noise. Hope you get this resolved.