iPhone X bootloop problem after screen and battery remplacement

Hi,

two weeks before i changed the screen and the battery and both worked good untill last day i found that my iphone x battery was drained ,

i put it in the charger than the problem of boot loop began and keep restarting untill it return to the battery low level icon , i was able to enter into dfu and recovery mode but my mac didn't detect the phone !!

i tried to bootup with the old battery without face id flex cable and yes it works!! the phone bootup normally then i made a backup , after the backup i restarted the phone and the problem of bootloop returns again and the battery drained again

my questions are, where is the problem in this situation ? is it the screen or the battery ? and how i can fix this problem ? what if i get a new battery and make the restore with should it will works ?

Thank you guys :)