So far, for me, the PCIE bifurcation issue only arose with the prospect of using a double or quadruple M.2-NVME to PCIE adapter with two or more M.2 NVME's. For my generation of chipset and mobo, only a couple boards feature bifurcation, and mine didn't.
If it were a matter of resolving this "Two-M.2/NVME drives in one PCIE slot", there are plenty of adapter cards available which resolve the bifurcation issue with an ASM2824 switch-chip.
But if it's a matter of sharing a PCIE slot between a dGPU and another type of adapter, it doesn't seem physically or practically possible.
I'd go with the other recommendations here, posted by other members.