John Jones has hired your law firm to represent him on charges of distribution o

John Jones has hired your law firm to represent him on charges of distribution of methamphetamine. (You chose state or federal court, apply the applicable Rules of Evidence, AZ or FRE). John tells you during the client intake interview that he was driving his brand new Tesla and had not received his plates for his car. The paper tag must have fallen off in the wind or the rain, when it was monsooning out. He was pulled over by law enforcement. John was kind of nervous and sweating, so the officer asked him to step out of the car and began searching. The officer searched everywhere, including the glove compartment, center console, and the trunk! John admits to you that he was nervous because he knew he had 2 pounds of methamphetamine in a gym bag in the trunk. Of course the drug dog found the gym bag and the methamphetamine. John didn’t know what was in the bag, but he’s been helping out his friend, Thomas. Thomas had asked him to take the gym bag to some guy over in North Scottsdale. John hadn’t been able to get over there yet. He’d always wondered what Thomas had given him, but he was too scared to look in the gym bag. John is scared of Thomas. John blurted out that the gym bag was his to the officer. The officer hadn’t asked, John just said it.
After that, the officer started asking him questions, and John told the officer everything. John told the officer about his friend Thomas (weird the officer seemed to know Thomas), and about taking the bag to North Scottsdale. (the officer even knew the address is North Scottsdale! So weird!). John was trying to be as helpful as possible to the officer and told him everything. The officer didn’t say a word, John just blurted it all out. John is scared and really doesn’t want to go to prison as he’s not a drug dealer, he was just being helpful, but now Thomas won’t even return his calls! Rude!
What constitutional issues can you raise as far the evidence and confession?