Hi M4000,
How did you back up the data from WhatsApp on your previous iPhone? If you used iCloud, you can restore from a backup which should include the data from WhatsApp. If you still have your previous iPhone available, you can make sure your WhatsApp data is backed up with these steps:
1. On your iPhone, iPad, or iPod touch, go to Settings > [your name] > iCloud.
2. Do one of the following:
* iOS 16, iPadOS 16, or later: Tap iCloud Backup.
* iOS 15, iPadOS 15, or earlier: Tap Manage Storage, then tap Backups.
3. Tap the name of your device.
Note: Although you can see all the devices that have iCloud Backup turned on, you can only change which apps are included in the backup for the device you’re currently using.
4. Turn the backup for each app on or off.
The apps list may be abbreviated. Tap Show All Apps to see a complete list.
Additional guidance is here: Back up your iPhone, iPad, or iPod touch to iCloud - Apple Support.
You may also find additional information from the WhatsApp website here: How to back up to iCloud | WhatsApp Help Center
Take care.