To disable iCloud backups, go to the Settings app and turn off Messages. After that, you'll be prompted to download messages from the iCloud backup. If you disable this feature, you'll need to cycle through the text messages on your iPhone to find the one you want. After completing this step, return to the Settings app and toggle off iCloud backups.
See also - https://emailspedia.com/recover-deleted-text-messages-on-iphone/
