My iPhone 8 is boot looping when charging

Earlier today my iphone 8 needed an update. After a few minutes it turned off even tho it was 89% charged. It turned on again when I plugged it in the charger, but the same thing happened again.. It turned off after half an hour and turned on when I plugged it in the charger. After an hour or so it turned off again, but when I plugged it in the charger it started boot looping until I took out the charger. I tried to force the recovery mode but it didn’t work. After two hours with me attacking all the buttons the connect to itunes logo finally appeared. I tried to update the phone because that seemed to be the problem. When the update was finished I tried to turn the phone on but the screen still was completely black and when I charge my phone it starts looping again. I’ve tried for like an hour to force the recovery mode but nothing is happening. I’ve never had any other problems with the phone and I really don’t wanna buy a new one.