What security measure is in force on your phone?
You might try a dirty flash as I described above. Do you have a copy of the iodéOS build that’s currently installed on the phone?
Once the dirty flash is done, and you reboot the system, it may pause a while at the Sony splash screen. That’s normal. If all goes well, maybe it will clear out the error that was causing the bootloop. If you get the bootloop again, try a hard reset. Maybe it will work this time.