Thats weird since the AOC-SLG3-2E4 should have a PCIe switch built in which should work in basically every board as it does not need support for bifurcation/lane splitting at all?
Agree, generic controller (no effort is needed for base functionality/enumeration - normally should detect automatically)
built-in motherboard bifurcation/splitting is not required with this card,
some sources suggest it's based on
PLX PE8718 Gen3 PCIe Packet switch (BroadCom says latency is around 162ns)
with 5 ports (I guess one is for upstream and other 4 are for downstream).