I also have one that goes about 45-50 mph / 72-80 kph. (Kaabo Wolf Warrior 11)
The limiting factors really are a. cost and b. common sense.
a. They're not cheap, being ~$2-4k and sometime take special shipping (freight) to arrive. And if you need repairs or service, the few major Kaabo dealers I've dealt with in the US are absolute amateur hour, fly-by-night trash. You're better off buying parts from AliExpress and repairing them yourself.
b. These aren't items to give kids or any under about age 17-20, depending on self-control, responsibility, protective gear, and suitable areas for use. Having a nanny state impose costs, limits, and regulations impinges on personal freedom... as the US has done effectively forbidden better foreign EVs (that won't participate in US homologation because there's no money in it). Any mode of transportation without a VIN, number plate, driver's license, and insurance already isn't allowed on highways essentially everywhere.