Afraid to tell you that it does not support bifurcation.  The storage specification for your system would only allow one NVMe drive be installed on PCIe x4 slot.  While the PCIe x16 will support other add-on cards, storage drive and thunderbolt are off limit.
If so, I can deploy a PCIe to M.2 adapter on x16 slot with pcie switch function enable.
Does T3640 support PCIe Bifurcation?