I guess so. However, you could also open a new thread specific to your needs.
Yes. It is not.
The mobo only has a single PCIe slot hooked up to four Gen3 lanes. While it’s thinkable to enable 2x2 lane bifurcation, your bios/uefi screenshots don’t show the option.
Yep. Have a look at the mobo manual. Figure 1-6 is the block diagram that explains how the 16 lanes are split up on the board.
- 4 lanes go to the PCIe slot
- 2 lanes are shared between m.2 slot and SATA
- the remaining lanes are used by other SATA, USB, Network options.
Realistically, you could add a maximum of 2 nvme devices to your mobo. The first into the m.2 slot, the second via a simple pcie-to-m.2 adapter card.
If you choose to install 2 nvme devices, that leaves up to 12 SATA ports usable for OS and zfs (this is the zfs thread after all).