iPhone thermalmonitord returned not alive but has never been opened.

I have an iPhone X that has never been opened for repairs or modifications but the thermalmonitord died all of a sudden while charging one night. I woke up to find my charging port unresponsive and my phone kept in restarting every 120 seconds. (I Timed It) I’ve seen responses for this issue but they are all people who opened it and did something inside. Mine has never been open and I just want to see if there is a solution or replacement for this obvious hardware failure and I just want to know what happened.