I have a problem dealing with a system set up RAID 5 with 8 hard drives, hard driver 1st Damaged

I worked a DriveSavers Data Recovery for over a decade and the best luck we had in setting up corrupted RAIDs with software is using UFS Explorer

https://www.ufsexplorer.com/ufs-explorer-raid-recovery.php

If you have EnCase, the images you have of each member disk can be added.  There is an EnScript that with read the disk images to compile a list of the possible permutations that may work.  Its then a case of trying each permutation until the right one is found, it takes some of the guess work out of the situation.  In respect of the disk that was damaged, EnCase will create a phantom disk, based upon the parity information of the other member disks.