No one with half a brain / common sense rides their ebikes at such speeds on pedestrian paths.
How would you prevent people who don't even have that from buying these bikes?
Don't prevent them from buying them, prevent people from riding that fast on sidewalks.
Another difference between e-bikes and scooters is that e-bikes do not require a license to drive while scooters do. One of the reasons for the speed limit on e bikes is to avoid this license requirement.
45 km/h e-bikes come with all the requirements that apply to 45 km/h limited scooters: license, plate, insurance, helmet.