Root hack i think
I have Cydia on nu iPhone 7 and i cant remove it. Nu phone het somtimes really hot while i am doing nothing on the phone van somebody help me whit that.
greatings
jean
iPhone 7, iOS 14
Yep, most likely it's been hacked as you jailbroke your phone.
You would have to fully restore it to have any chance to using it again, by using Recovery Mode.
Ref: How to Get Into and Out of iPhone Recovery Mode - Lifewire