iMessages in iCloud cannot be sent to new iPhone

After my iPhone crashed many years ago it partially restored and while plugged in and connected to WiFi it completed an iCloud backup before being full restored. This became the primary backup leaving the iMessage history only partially restored.

The full history of iMessages still exist on my MacBook but GeniusBar says that those cannot be migrated over to the iPhone because they’re on separate backups.

My argument is that if they’re in the cloud, they should be accessible from any device linked to my iCloud account.

Does anyone have any idea of how to restore these messages back onto an iPhone?