In that clip, Djokovic's flat hitting deep to the baseline causes Nadal to cough up a shorter ball. And then an even shorter ball. And finally Djokovic gets that angle because he's halfway up the court already. All the backhands he hit were relatively flat.
It's different from hooking someone off the court from your own baseline with viscous topspin. The backhand Federer hits at 0.08 in the following video is an example of that;
...and Federer doesn't even hit nearly the most topspin anyone has ever hit with a 1hbh.
Let's be clear, the 2hbh is very good for taking the ball early, hitting it deep, changing directions and rallying consistently. These are all things that the 1hbh can also do, but it is much
easier to accomplish them with the 2hbh. Currently, Djokovic is the best in the world at doing them.
However, hitting absolutely crazy amounts of topspin off the backhand is something only the 1hbh can do, because of the wrist range-of-motion, and the longer stroke allowing for more acceleration.
This is why I think that the 1hbh has the higher ceiling - with the 2hbh it is easier than a 1hbh to do 90% of the things a backhand can do, but there is a remaining 10% of things a backhand can do that can only
be done with the 1hbh.