I've never owned or looked at the inner workings of an e-scooter before. But I can venture a guess. Locate the controller and look for a connector that comes out of it, goes to a quick connect, and then just goes right back into the controller. It might be labeled hi speed/low speed or something like that. Disconnecting it is probably all they do when they sell in countries with speed restrictions. There's no much helpful in the user manual about the subject.

Good luck in whichever country you intend to ride it in.