While it's not quite as high speed as DDR4, I've designed some simple PCIe board with KiCAD (OCuLink to PCIe x4, M2 A+E to 2.5GbE). It does require some hand-ho

While it's not quite as high speed as DDR4, I've designed some simple PCIe board with KiCAD (OCuLink to PCIe x4, M2 A+E to 2.5GbE). It does require some hand-holding though. Edit: Completing comment