Google announced that WhatsApp's chat history migration feature for transferring messages from iPhones and Android to Android is now available to all Pixel phones. It will also be available to new phones that launch with Android 12 but it won't require you to lose your messaging history.
It should not be difficult if you have WhatsApp installed on your iPhone and Android phones, and a USB-C cable to connect to your Lightning device. Google states that when setting up your Android phone you will be asked to scan a QR code using your iPhone. This will allow you to begin the transfer process.
For more information, see our how-to (it was written for Samsung but they should work for you) and to learn about the limitations of the transfer. Google claims that you won't lose any WhatsApp messages from your iPhone while your messages are being moved.
Google's statement that the feature would be available to new phones that launch with Android 12 is unclear if existing devices that have received an Android 12 update can make use of it. We have reached out to Google and will update this story if they respond.