So I bought a cheap 50$ 500W controller and hooked it up. Don't forget to buy one made explicitly for motors without hall sensors, as the 3.0 motor has none - just some wires connected to feedback windings.
Works ok, but this scooter is only fun to ride on smooth streets. You definitely need air tyres. Max. range at 30km/h is about 20km; although after 10km speed drops to 25 km/h