BSOD is sign of unstable RAM, constant freezing (I think) and if your RAM dies, your PC is unusable until u get new RAM.
You can always check your RAM health with Windows Memory Diagnostic or Memtest86
i5 8400 is better in this case cause whole platform has good budget mobos and you can upgrade later to 6c/12t i7 if you want to while with i7 7700 you are getting dead end on platform.
Get this RAID card and flash it to IT mode.
Also I would recommend using FreeNAS instead of openmediavault cause of much larger community that can help you and much better interface.
FreeNAS thread for flashing into IT mode.