iPhone X stuck at Apple Logo

Hello - while attempting an iCloud backup of my phone (roughly 250GB of data backing up), my iPhone X (software version 13.5.1) went to the Apple icon after about an hour of backup up data to the cloud.

I cannot get it off of the Apple icon. I have tried clicking the volume up, then volume down, then holding the side button, but it will not go into recovery mode. The phone just flashes black, then goes right back to the Apple icon.

Any advice?