To try to get the driver approved, reinstall SoftRAID driver. then wait, or navigate to System Preferences/Security/general adn "Allow".

If the option is not there, then there is a macOS issue. I would boot with command r and "reinstall macOS" it wil not affect your system, but will take a hour or so. Then try installing the driver again and see if the Allow option is available.

Error Domain=KMErrorDomain Code=27 "Extension with identifiers com.owc.driver.SCSI-Device0E,com.softraid.driver.SoftRAID,com.owc.driver.SATA-Command,com.owc.driver.SCSI-Device not approved to load. Please approve using System Preferences." UserInfo={NSLocalizedDescription=Extension with identifiers com.owc.driver.SCSI-Device0E,com.softraid.driver.SoftRAID,com.owc.driver.SATA-Command,com.owc.driver.SCSI-Device not approved to load. Please approve using System Preferences.}

While scouring System preferences, I am not seeing where to approve the RAID volume as mentioned in the Terminal output. I did confirm that SoftRAID 6.1 is allowed to run in Accessibility and Full Disk Access. I also saw that SoftRAID Monitor was unchecked, so I checked it and ran Terminal again. The output changed to this:

Error Domain=KMErrorDomain Code=27 "Extension with identifiers com.owc.driver.SATA-Command,com.owc.driver.SCSI-Device,com.owc.driver.SCSI-Device0E,com.softraid.driver.SoftRAID not approved to load. Please approve using System Preferences." UserInfo={NSLocalizedDescription=Extension with identifiers com.owc.driver.SATA-Command,com.owc.driver.SCSI-Device,com.owc.driver.SCSI-Device0E,com.softraid.driver.SoftRAID not approved to load. Please approve using System Preferences.}

The RAID volume only mounts after a restart. I am unable to mount the RAID volume from within SoftRAID. 

I don't know if this is related, but I do have another thread going on another forum page https://forums.softraid.com/functionality-issues/softraid6-always-needs-administrator-authentication/paged/3/#post-12073 where we've just discovered that, despite best efforts, the SoftRAID driver is stuck at 6.0.5 while running SoftRAID version 6.1. 

What is the error output to this command in terminal (paste it in)

sudo kmutil load -p /Library/Extensions/SoftRAID.kext

Or does your volume mount?

thanks!

Thank you for your help!