Restoring from back up, iPhone now frozen

I plugged my iPhone 11 to sync with iTunes, the phone is quite new so I hadn't connected to itunes on the mac with it previously. It asked if I wanted to restore from a backup which I did. This took about an hour or so, then when finished it said wait and your phone will restart shortly. At this point it showed the apple logo on the screen, the logo stays for a while then flashes off, then on and off but the phone since will not switch on or off and doesn't do anything at all I tried the hard reset, still nothing.