It could take up to 24 hours for all of your content to download from the cloud including all of your apps, app data, photos and so on. However, your phone should not be stuck on that screen for this long. By my calculations it’s been that way for at least 3-1/2 hours and that just isn’t right.
Personally, I would try a forced restart and see what happens. I don’t know if you will ultimately have to restore to factory settings and then restore the backup, but if that progress bar has been stuck for over 3 hours, it’s not going to go any further anyway, IMO.
If you care to try it, In order to perform a forced restart, Press and hold both the Home and the Top (or Side) buttons until you see the Apple logo.
That will (should) cause the phone to restart and then if it does you should be able to start over again.