how long for software update on brand new iphone 14

This thread looks a little baked, but I had the same problem posted here. If you've followed the prompts for transferring to a new iPhone, it gets just about done, and then it says it has to update software and the interminable click wheeling begins, plug your new phone into your Mac, it will take over the transfer from an iPhone backup, and show you the progress. When it was done, there were some screens to navigate, but otherwise the transfer went smoothly and quickly. The only catch, of course, is you want your iPhone backed up to your Mac, so you should check that before you do this.

It is doing the same for me. Did yours ever start working?

If your screen is stuck on the "software update" screen, hold down the power button and press "shut down." Turning the phone back on will refresh it and start transferring the data.