For ASrock, the top PCIe slot can be configured as 4x4x4x4, so go ahead and pop in a dumb 16x4 u.2 or m.2 HBA. My 9950x currently has ~30TB of NVMe 3/4 storage attached, which is an amount I'd comfortably call "enough." dd tends to have one high-end system at a time, and even with only 4x SATA...