I just was migrating my server over to a new Norco case, this one specifically, https://www.newegg.com/Product/Product.aspx?Item=9SIA3913UN3405 Norco NORCO RPC-4116. It just has simple SATA connectors in the back of the plane so I thought I would be fine. Unraid doesn't seem to see any drives and I get a ton of "SATA link down" when I'm watching the boot up (it says this for 14 drives, 8 connected to the mobo, one 8 port card flashed and one 4 port card flashed). This is also a new motherboard, an Aorus GA-AX370 UEFI motherboard. Is there some weird SATA setting that I'm missing that would cause unRAID to not see any of my disks?

It's not a compatibly problem, these use direct SATA connections, if they're not working there's a problem somewhere, either wrong cables, no power or a malfunctioning case.

I hope I have found the issue. One of the pins on one of the backplane was cracked. Just emailed Norco and fingers crossed they'll just send me another backplane. I hope swapping this out isn't too much of a pain. Will report back.

While you wait, you could try plugging in a few drives directly and see if they are visible. You could probably fully configure your system with the drives just stacked beside the server (not recommended for long term use) as unRAID remembers drives based on their serial info.