You should understand why there is a top speed lock to the 450x it’s not because Ather does not care about top speed on 450x but it’s because it will kill the battery much quicker and also for a city 2 wheeler it’s not at all needed.
You can expect higher top speed in new models which have higher batter capacity and which can be taken outside to travel longer ranges like 250 to 300km. 450x has speed limitations for good.
It’s the quickest Scooter out there in the market. Fastest matters only on race track and not in city roads