All fair points but it is quite an undertaking to build an ebike that does 60km/hr with a useful range. Heavy motor, serious AH high discharge battery and a controller that can handle those amps. Your battery system will need to be above 48volts. Pushing wind above 35km/hr requires a lot more energy for each 5km/hr gain.

45-50km/hr idea fairly easy though with a 48 volt system.