According to apples support page, your iPhone COULD pose a viable threat to your life. The magnets in the iPhone 12 have been found to be able to interfere with some medical devices such as pacemakers or defibrillators.
Apple suggests to NOT keep your hone in your shirt pocket if you have one of these devices installed. The newer iPhones had more magnets contained in the device than prior iPhones and have been found to disrupt the functions of these medical devices. They recommend that you keep your phone at least 6 inches apart, or 15 inches apart when wirelessly charging.
Apple also says you should avoid placing credit cards, security badges, passports or key FOBs between your phone and your wireless charger, because the magnets could possibly damage magnetic strips or RFID chips.