[ADefenestrator]

Even if it had slots for the splitter cable, Intel and AMD onboard SATA explicitly doesn't support port multipliers as far as I know. You can buy PCIE SAS cards that do for relatively cheap, but then you have to find board with enough PCIe slots. Easy enough on the "gamer" boards but if you want ECC (and you probably do, for storage) and IPMI (you probably do, if you have more than a few dozen servers) your options get much more limited. Other than 1 or 2 Asrock Rack boards, you pretty much have to move into Epyc 7000-series or Xeon Silver or above. Often dual-socket on the Xeons to get a board with lots of PCIe.

In theory something like an Epyc 3000-series with lots of PCIe or onboard SATA that supports port multipliers would work great, but I don't think anyone actually makes that.