Can the backglass cover be replaced?

The 14 Pro can have the back glass replaced, but typically its something that Apple would replace most of the chassis for It's called a rear System, which would basically keep the screen and camera from the existing phone, but get new everything else. In fact batteries will always get replaced if they are removed in a repair by Apple.

Depending on how bad the break is,m its possible that other parts were affected, but likely a third party shop could replace the back glass for you for a reasonable price. There re sometimes some issues with the wireless charging coil. Because of Apple repair complications, but any respectable shop should be able to handle that. The 14 and 14 Plus have a much easier process. the 14 Pro and Pro Max are actually the last iPhones to have difficult back glass repairs.