Iphone 13 pro max respring and restarting issue.
can anyone help me diagnose an issue? ive done multiple search efforts to no defined answer including having it "repaired" . all help appreciated.
My refurbished 13 pro max has been often restarting and respringing unfortunately after the month grace period it came with. The repairer i went to said its a software fault or a "mystery" on multiple occasions, the phone usually works after a restore for a few days before it starts to turn off or respring alot, or just plain turn off sometimes. other symptoms after rebooting include purple screen flickering, frozen screen, undetected E-SIM, face ID not working, the camera not launching and apps force quitting immediately usually followed by a restart. The phone even resprings upon setting it up after restore sometimes. Physical symptoms arent showing up apart from the top left corner of the phone being warmer than the rest of it. I havent water damaged the phone in any way, ive only ever dropped it from couch height and I dont use it on charge or put it under stress at all. Often the phone will bootloop after a failed restart and sometimes send me to the recovery screen but detects no issues.
iPhone 13 Pro Max, iOS 26