Raid will not mount.

SoftRAID is not a file system manager. It does not talk to files, it cannot "repair" a volumes interior, SoftRAID only manages the volume containers.

So when a volume is damaged, validate or verify will not fix the problem.

Volumes not being mountable can be from kernel panics, accumulated unclean shutdowns and also problems when MacOS is upgraded.

When your system shuts down, MacOS closes the volume directory on all mounted volumes, then unmounts them. If the unmount happens cleanly, a bit is toggled to "on". That is a clean shutdown, the normal process. At startup, macOS checks that "bit" to see if the volume was unmounted correctly. (called the dirty bit)

If MacOS detects there was an unclean mount/shutdown, it automatically runs a repair tool (fsck essentially) to repair any directory damage. (its not a comprehensive tool, its pretty basic)

if this tool fails, the volume is usually marked read only, a dialog box is posted warning the user the volume is damaged, and then mounted. Sometimes the volume cannot be remounted so MacOS can no longer mount the volume. That is the condition you are in.

Since this is MacOS failing to repair, it can not do any further repairs. Your choice is restore from backup, use a "recovery app" to recover your data, then restore, or "repair" your volume directory.

The only macOS HFS file system repair tool is Disk Warrior. Its a great program, been around 25 years, but is a commercial paid application.

If you choose not to purchase Disk Warrior, you will need to restore your data from backup or file recovery. There is no HFS volume repair option from Apple. If you want to "recover" your data, the two best applications I have tested to work are Disk Drill and R-Studio.

If you choose Disk Warrior, I can help with instructions, its straightforward, but you want to make sure the volume is what you expect before clicking "replace", which is not undoable.