Reddit mentions of Mini SAS SFF-8087 to M.2 x 4 with 3.5 Inch Frame

I looked closer at our chassis setup and it is 4x 5 slot boards, so I'm not actually sure what protocol they run because SAS breakouts should max at 4. We're definitely proprietary compared to the options I am seeing online.

Closest equivalent commercially available part would be something like https://www.amazon.com/Mini-SAS-SFF-8087-Inch-Frame/dp/B00M36C2KK which effectively breaks out an internal sas port to 4x sas/sata interfaces. Looking online the DL320 should have an unused onboard port.

Alternatively https://www.amazon.com/Aplicata-Quad-NVMe-PCIe-Adapter/dp/B01MTU75X4 or https://www.aliexpress.com/item/NEW-The-adapter-card-PCI-E-16X-TO-4P-NVMe-SSD-Support-RAIDO-PCI-E-16X/32951136605.html will let you run NVME directly off the PCIE slot assuming there isn't some other expansion already there.

So in a dl320 you could probably do one of each so long as you have physical space left and you don't run out of power.

Forgot one other option, which assumes OP can find power and mounting points on their own. https://www.amazon.com/Cable-Matters-Internal-SFF-8087-Breakout/dp/B012BPLYJC