How to set up SSD as Boot Drive and Raid 1 HDDs as Storage Drive

[Super_Spunz]

I currently have a Gigabyte GA-H270-HD3 on BIOS Version F8, a Samsung 980 500GB M.2 SSD, and 2 Seagate BarraCuda 2TB HDDs. I want to use the SSD as my boot drive, and the HDDs in RAID 1 as my storage drive, as the title says, but everything I've tried so far has broken something. The most prominent thing I've noticed so far is that for RAID, my motherboard requires BIOS > Peripherals > SATA and RST Configuration > SATA Mode Selection to be set to "Intel RST Premium With Intel Optane System Acceleration" but when I select that, Windows gives me a "Inaccessable Boot Device" code and I can't boot into my SSD. When I set it to "AHCI," I can boot into my SSD just fine. 

 

Any suggestions for how I can get this working? Should I just use software "RAID" through Windows instead? I've heard that software RAID is slower, so I would rather use hardware if possible.