Nvme storage question on Taichi x870e mobo

Look at the page 11 (as printed) / page 15 (pdf file) of the user manual.
The two PCIe slots can run either as x16 / disabled or x8 / x8.

Now, the question is, what does that PCIe -> m.2 x 2 card do?

Based on ASUS page: "** When ROG Hyper M.2 card is installed on PCIEX16(G5)_1, PCIEX16(G5)_2 will run x8 only and if ROG Hyper M.2 card is installed on PCIEX16(G5)_2, PCIEX16(G5)_1 will run x8 only," I'm guessing that the card itself has no logic and depends solely on motherboard's ability to bifurcate.

I'm assuming Taichi x870e can do x4/x4 bifurcation, at least on one of the PCIe slots. And if so, you should be able to use the m.2 splitter card on that slot, once BIOS setting for bifurcation is set properly.

Now, I'm not sure if you can do this independently for the two PCIe slots. For example, if you want to use the top PCIe slot for GPU, then you'd want x8 + x4/x4. If you want to use the bottom PCIe slot for GPU instead, then you'd want x4/x4 + x8. No idea what configurations the motherboard supports.

The other possibility is that the PCIe -> m.2 x 2 card has built-in PCIe bridge. If that's the case, it should just work, if with a slight bandwidth / latency handicap.