Check the Recently Deleted folder in the Messages app
Open Messages
Tap Edit or Filters
Tap Show Recently Deleted
Select the messages
Tap Recover
Restore from an iCloud backup
Go to Settings
Tap your name
Tap iCloud
Tap iCloud Backup
Restore the iPhone from a backup made before the messages were deleted
Restore from a computer backup
Connect the iPhone to a Mac or PC
Open Finder or iTunes
Select the iPhone
Choose Restore Backup
Pick a backup made before the messages were deleted
Check other Apple devices signed in with the same Apple ID
Open Messages on iPad, Mac, or another iPhone
Look for the deleted messages
Contact your carrier
Ask whether message records or backups are available
Use a third-party recovery tool
Connect the iPhone to a computer
Scan for deleted messages
Recover any found messages