A: First please check if you use the USB Type-C power adapter, if yes, please change to use DC power adapter topower via DC jack of X882 to test. The USB Type-C PSU maybe not enough to power the dual HDD/SSD.
Q6: Why only one SSD/HHD can be recognized?
A: You choose the RAID1 mode, because it is a hardware RAID, so OS recognize only one HDD/SDD.