New iPhone, all messages, apps, bookmarks etc deleted

If you can't back up to iCloud or restore from iCloud backup failed

Learn what to do when you need help with an iCloud backup of your iPhone, iPad, or iPod touch.

If you need help after you tried to back up in iCloud or to restore from an iCloud Backup, use these steps.

Get help backing up your device in iCloud

Get help restoring from an iCloud backup

Get help backing up your device with iCloud Backup

Learn what to do based on the issue that you experience or the message that you see.

If an alert says that there's not enough iCloud storage

A message appears when you need more iCloud storage to back up (the available space on your iOS device is different than your available space in iCloud). Before proceeding, you need to know your Next Backup Size and how much iCloud storage you have available.

Here's how to find your Next Backup Size:

• On iOS 11 or later: Go to Settings > [your name] > iCloud > Manage Storage > Backups. Tap the device you're using.
• On iOS 10.3: Go to Settings > [your name] > iCloud > iCloud Storage > Manage Storage. Tap the device you're using.

If a message says that your last backup couldn't be completed

1. Check that you're connected to Wi-Fi.
2. Ensure your device is up to date.
3. Try to back up on another Wi-Fi network.
4. If you still need help, contact Apple Support.

If you’ve already attempted to restore your device, and you’ve received an error, you’ll want to do the following:

1. Erase the device and set it up as new.
2. Check your software version and confirm that it’s up to date.
3. Confirm that you’re connected to WiFi.
4. Erase the device and try to restore from your iCloud backup again.
5. If you still need help, contact Apple Support.

If the backup you want to restore from doesn't appear on the Choose a Backup screen

1. Confirm that you have a backup available.
2. Try to restore your backup on another network.
3. If you still need help, contact Apple Support.

If you're missing data after restoring from a backup

Learn what to do if you're missing information after you restore your iOS device with iCloud Backup.

If you can't back up to iCloud or restore from iCloud backup failed ...

https://support.apple.com/en-us/HT203516

If the backup was created in iCloud, restore again from that backup:--> Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Regards

Giulio