Manual transmissions are good and more efficient than running without one. Electric motors have efficiency curves too and proper gearing extends range, even if they can function well without shifting. Many choose single speed for the simplicity, but it isn't the most efficient. Others use 2 motors joined by a differential, creating a CVT to keep the main drive at peak efficiency.
You see this in the electric bike world too. The cheaper ones use a direct drive hub motor. The higher-end option is a mid drive that takes advantage of the rear sprocket gears.
To be able to go highway speeds and crawl well you're probably going to need a low-range option.
