Oculink splitters

My mobo has two Oculink connectors, one is a PCIe4.0 x4, and the other a PCIe3.0 x4. I don’t suppose I can split these into 4xPCIe4.0 x1 and 2xPCIe3.0 x2 respectively, can I?

I am obviously looking to accommodate as many M.2 NVMes as possible, while all the while reaching at least 10Gbps per drive.

Could this and this be the answer?

Anyone has any experience w/Oculink splitting?

[Edit: yeah, I now realize that the same issue arises all over again: the cables mentioned above are passive, so if there is no bifurcation on the mobo at the Oculink connectors, only one drive will be recognized. Bummer.]