iPhone 6 Reboot loop after repair

I have an iPhone 6 which is stuck in a reboot loop,

ive tried to restore and update using iTunes, multiple times, but I keep getting error 4013.

ive tried putting it in DFU mode, but can’t seem to as phone constantly reboots when I connect it to my PC.

Could it be a battery problem? Or software? Please reply if you have any info, thanks