There is no way DJI have done some miracle with motor or battery tech to give the same range from a 600 as the Bosch system from 750.
But if they did, well, then you can't use capacity as a valid comparison, its the range that matters.
And that would be brilliant for us as riders, same outcome for less weight/size etc, sign me up for that!
I'll take a 400wh battery/motor system that gives me the same range as a 800wh every day of the week please....
But there won't be a huge jump in motor and batteries efficiency to achieve this more than small iterative steps.
There are so many variables that effect range from rider weight, to temperature etc that there is nothing that they can put out that you can't say, what about this scenario.
Its going to be something 750ish.....
IF you think 800ish is not enough for you, then you'll have to pick a bike with 1000, or a range extender.