Why is my Iphone 14 pro dying so fast

I am facing an ongoing battery drain problem with my recently purchased iPhone 14 Pro (March 2024). The battery seems to be depleting rapidly, even when the phone is not in use. For instance, this morning, the battery dropped from 100% to 90% within just 15 minutes while the phone was on my nightstand.

I have sought help from Apple twice, but unfortunately, the issue remains unresolved. During my first visit, they suggested that the problem might be related to my charger, so I purchased a 20W block as advised. However, this did not improve the battery life.

Feeling increasingly frustrated, I visited another Apple location a few days later. They thought the problem could be software-related and guided me through a hard reset, setting up the phone as new. Regrettably, the battery drain issue persists, with the battery depleting by 3% every five minutes.

I requested a battery replacement, but Apple declined, stating that my battery health is still at 100%. Despite this, I strongly believe that the battery is faulty, as I have never encountered such problems with any of my 12 previous iPhones.

I have exhausted all the troubleshooting steps suggested by Apple, yet the issue remains unresolved. I am eager to find a prompt solution to this battery drain problem and would greatly appreciate any suggestions or guidance. Thank you for your assistance.