Here’s my take on this. You have a few options, each with trade-offs.
First, check the ‘Recently Deleted’ folder within your Messages app, as newer iOS versions have this feature—it’s the quickest potential fix. If that doesn’t work, your most reliable path is restoring from an iCloud backup that was made before the messages were lost. The pro is that it’s an official method, but the con is significant: you must completely wipe your iPad and will lose any new data added since the backup.
Alternatively, third-party recovery software can scan for deleted data without a full reset. This is more convenient, but success isn’t guaranteed, as the data might already be overwritten. It really comes down to how critical those messages are versus the hassle of a full restore.