Possibly this was due to some problem other than an actual failed disk. Connection issues are far more common than bad disks. Perhaps it wasn't even necessary to buy another disk.
Disk4 isn't showing up in SMART in those diagnostics. Often when mucking about inside the case, such as when replacing a disk, the connections of other disks will be disturbed. Possibly this is what has happened here.
Shutdown, check all connections, all disks, SATA and power, both ends, including any splitters.
Reboot and post new diagnostics.