What options are available to rescue deleted text conversations for iOS 15.7 users?

IF you have not turned on iCloud Messages and IF the text conversations are in your last backup you can restore your iPhone from that backup. You will lose any data added since the date/time of the backup your restore.

I have this question as well. I took my iphone 6s to be repaired at my local apple store and they recommended not to restore from I Cloud backup so I have had to reinstall all my apps. The Whatsapp and Messenger messages are all visible but not the Text Messages. Are they gone for good?