That icon is telling you how long the shutter will stay open while taking the photo. Adding more light to the subject will allow the phone’s camera to take a faster photo.

As a person who used to work with Apple tech, if you didn’t have an iCloud back up of your phone (for potential local storage backup of your lost photos), or a local back up on a pc of your phone of the photos that are not in iCloud, they cannot be recovered. During a restore the Apple device does a secure wipe of the storage on the chips. What you see when you sign back into your iCloud account in terms of contacts is what was already there, and was re-downloaded once you signed back into your account. I’m am truly sorry for the loss of what are possibly very precious memories.