messages
How do you retrieve messages from your icloud backup?
iPhone 11 Pro Max, iOS 13
If you were using iMessages in iCloud, then your messages are stored in iCloud. If you deleted it there, then they're gone. If you weren't using iMessage in iCloud, then you can restore from a backup.
What does iCloud back up? - Apple Support
Restore your iPhone, iPad, or iPod touch from a backup - Apple Support