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