What data repair and recovery options exist for a missing APFS Volume?
Solution 1:
How to Recover Lost Data from APFS Volume on Mac
https://recoverit.wondershare.com/harddrive-recovery/how-to-recover-lost-data-from-apfs-volume.html
It will cost you $40
or this one https://www.ibeesoft.com/data-recovery-software/mac-data-recovery.html
You can always try to do it your self with Disk Utility.
https://blog.macsales.com/44912-new-capabilities-limitations-how-disk-utilitys-restore-feature-changed-in-high-sierra