Heavy utility cycles will become a very large part of transportation as people wake up to the reality of climate change. It is not easy to understand how to provide enough low-speed torque thrust that is needed to climb steep hills at legal speeds. Bigger motors are not the best solution. Proper gear to power matching is much more efficient and economical, especially in terms of mileage.
Many people confuse torque with power. They are different terms. Motors can have high torque-thrust at slow hill climbing speed, or low torque-thrust at a high top speed and yet have similar power output.
Measure the steepness of the worst hill that you cannot avoid climbing. Use a level and a ruler (metric or decimal), then divide rise into the span to get the grade percentage.