Two SSD's won't mount - formatted APFS

I have two Samsung 850EVO 1TB SSDs formatted APFS in an external OWC Thunderbolt 2 External Drive Dock. I am running HIgh Sierra on 2013 Mac Pro

The two SSD's have failed to mount, and I cannot repair them. It's not the end of the world, I have backups except for a couple hours I would prefer not to lose. These are media drives for FCPX.

The device shows up in disk utility, the volume is greyed out and disk utility cannot repair. This is what first aid shows:

error: om: invalid o_oid (0x1e88)

Object map is invalid.

Storage system check exit code is 8.

Storage system verify or repair failed.

Operation failed…

My biggest concern is I also have two Project Archive Hard disks, and I have both formatted APFS. I always counted on the odds of a dual simultaneous failure as acceptably low. Now I'm thinking with this problem I should only have one formatted APFS and one formatted Mac OS Extended to be safe. Also thinking of formatting my external SSD's

back to Mac OS Extended.

Any help would be much appreciated.