iPhone overheats while playing Apple Fitness+ with the screen off

I may be the only one experiencing this but in case I’m not I wanted to discuss this issue. I download my contents for Apple Fitness+ onto my iPhone 14 Pro before going to the gym, when I play just the audio alone (not streaming) I notice that after a 10 minutes my phone is noticeably hot. And before I dive deeper answering questions of potential user error allow me to specify: I only use Bluetooth audio on my AirPods. The iPhone is not in direct sunlight and it’s not plugged in or charging. The screen is off and I’m just listening to the instructions while exercising. The reason why I use only the audio is that it’s hotter with the display on when I used my iPhone 11 and thought turning off the display would lessen the heat. Some of these sessions are 45 minutes and I’m concerned because it’s already hot after 10 minutes. I’ve checked to make sure it’s not doing anything else (all apps closed) except the sessions on Apple Fitness+. Anyone experiencing this issue?