iPhone XR black screen after software crash, restart failed

My 4 yr old iphone XR screen, although newly replaced, just shows a black screen but is still on as I can feel the unlock toggle and siri responds well. I’ve tried the restart process (push and release volume up/down, push and hold power button) but doesn’t seem to work for me. I suspected a software crash might’ve caused the issue as I’ve woken up to a screen with lines before blackening out. I can’t give it up yet because some photos haven’t been backed up to icloud.