So you retrofit a Rohloff 14 to the MD 1000? I wonder if anyone has ordered the MD 1000 with the Rohloff 14 from Leili? I have the Rohloff E14 on my current bike and it is indeed "amazing" but it is an electronic shifter that is fully integrated with a smallish Bosch mid-drive motor (75Nm) that has auto cutoff when shifting to protect the E14.
As long as you ride carefully e.g. not shifting under load I imagine that would be fine but a 120Nm motor can be a drivetrain shredder. The horrible experience with the SA RX-RK5 taught me how to shift without pedal or motor power engaged and I continue to do that today. The MD 1000 is certainly not a "mountain bike" and anyone who buys it for that use case will find that out pretty quickly. It's a cool looking big, fast, fun cruiser that can go just about anywhere but riding it like a mountain bike is a good way to maim it, or yourself.