iPhone running slow, overheating, draining fast

Solution 1:

I have seen phones that need a restore on occasion. I would do that and when you sign in - do not restore any backup. I also would not install any third party apps, sign in to any cloud accounts and just use Safari for an hour to see if you feel it’s substantially better with a clean restore.

  • https://support.apple.com/en-us/HT204184

Erase all contents is not sufficient - you will want to connect to a computer and restore it. Again, make sure you get a good backup or two, just don’t restore them initially while you test the hardware.