Huawei P 10 Plus SMS deleted, how to recover?

If there is a backup that can be restored, you can see the "backup record" of the previous backup after entering the "backup" application. If there is no backup, it cannot be restored.

Backup: If the system hardware or storage medium fails, the Backup tool can help you protect your data from accidental loss. For example, you can use backup to create a copy of data on your hard disk and then store the data on other storage devices. The backup storage medium can be a logical drive (such as a hard disk), an independent storage device (such as a removable disk) or an entire disk library or tape library organized and controlled by an autochanger. If the original data on the hard disk is accidentally deleted or overwritten, or the data cannot be accessed due to a hard disk failure, you can easily recover the data from the archived copy.