Update could be stuck or corrupted. Need to put device in DFU mode and restore using a computer. And that's if it's software related. If it's hardware related like logic board issues then there is no fix unfortunately.

sorry I'm not really well versed in all of this what's DFU mode? and how can I tell if it's a hardware issue? the phone does get very hot when updating

It's recovery mode. I'll post the link to the support page, it will guide you on how to do it just make sure to follow for your specific phone as each phone is different.

https://support.apple.com/en-us/HT201263#:~:text=1%20Make%20sure%20that%20your%20Mac%20is%20up,with%20these%20steps%2C%20but%20don%27t%20...%20See%20More

Getting warm it typically normal as phones don't have fans so they disperse the heat across the device when doing hardware intensive tasks. And if you follow the steps in that article and the issue continues it could indicate an actual hardware failure.

I'll try doing an ITunes restore one more time if not then will I have to get the interior replaced?

Unfortunately for that device there is no hardware repair directly from Apple for that issue