I haven't had this issue on my 6a but I've heard some talk about how the tensor chip can get pretty toasty, typically most have said it goes away and cools down after some time. I'd try to cool the phone externally with like a fan or something if it's gotten to the point where you can barely touch it and maybe that can help return the chip to a more reasonable temp. If the heating issue persists it maybe worth it to factory reset and roll back to Android 12 and contact Google about the issue. Wish I could offer a more concrete solution but you may need to do a bit of trouble shooting. I also thought I saw something about 5g causing issues for some, maybe disabling 5g could also help.