S21 ULTRA restarting

[Kas63]

I've had the s21 ultra for about 2 year and a couple months back the screen went blank so I sent it to samsung repair while in warranty. About a week or 2 after the repair the phone started to randomly restart but left it as is. Now phone is frequently restarting and then bootlooping. Tried safe mode and still occurs. Wondering what the issue could be and also my warranty has since expired so would it be costly to repair

[thebellone]

A very common fix going round is to perform a Factory Reset, which I did, and I still have the same boot loop problem. My phone now is absolutely useless now as it restarts almost immediately it boots up, allowing no time to make use of the phone. This is my first Samsung phone and will be my last, as Samsung are not engaging with their customers on this issue at all.