Welcome to the forum.
Your Yamaha makes 68NM at 6800 RPM measured at the flywheel. But imagine if you were to measure that at the axle, in first gear. If you have a 10 to 1 ratio for first gear, your back wheel would spin at 680 RPM (10 times less) but have 680nm torque. (10 times more) Yeah, I'm ignoring mechanical losses to make this easier.
That's what the electric scooter companies are doing: Cherry picking where they measure the torque. Also, an electric motor makes max torque at zero rpm, and the torque drops off in a straight line to it's max RPM. So starting off you have a huge amount of torque, but as your speed increases, your torque drops. That huge torque at start is why electrics often don't bother with gear boxes. 1 speed is all they need.
That's why the Zapp compare's it's self to a 300cc, and the Vespa is probably closer to a 80cc bike. The zapp has a 14kw motor, about 18.7 horsepower. the Vespa has a 4kw, 5.3 horse power motor. Compare that to 67 horsepower from your Yamaha.