How to restore deleted text messages in iPhone 11

Assuming you don’t house your messages in iCloud m they are saved on your iPhone backup. Restore that backup to retrieve the messages that were present when the backup was created.

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

IF you have not activated iCloud Messages, and IF they are in your last backup then restore your iPhone from that backup. You will lose any data added since the date/time of that backup.

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

How to recover deleted text messages on iPhone - Macworld