Phone randomly locks up and reboots

The only way I've fixed this is by putting it in the freezer. After I bought and installed another battery, it no longer bootloops and it doesn't freeze up and reboot as fast as it did with the old battery. OEM Unlocking was never on, not even USB Debugging.

The phone however does not freeze up and reboot in the recovery or download mode, making me think that the battery was the issue at first, which it kinda was.

I've also reflashed the os with Odin with CSC (which wipes the phone) and I have also formatted it in the recovery. I've flashed older versions and the latest versions to no avail.

So is my motherboard screwed? Or is there something I'm missing here.