Recover WhatsApp Chats on iPhone

I need help restoring my WhatsApp chats on my new iPhone. I backed up my WhatsApp on iCloud before transferring to my new phone. After the factory reset on my old phone, I cannot access my old chats. I'm being prompted for a password or encryption key that I don't have.

Requirements:
- Recover 14GB of WhatsApp chats
- Use iCloud for backup and restore

Ideal Skills and Experience:
- Experience with iCloud and WhatsApp restoration
- Troubleshooting iPhone backup issues
- Familiarity with encryption keys and WhatsApp security

I have the iCloud account credentials. Please help me get my chats back!