Braces is used in one, regains balance is used in another. Simply maintains possession long enough is used in yet another. It is the one that simply says maintains possession long enough that I was getting hung up on as being in contradiction with the actual going to the ground rule. But it you put the three into the same context, IMO the intent is that if the player starts to go to the ground, but yet "gathers" themselves in a meaningful way for long enough, and then performs a lunge, then they will make an exception to the going to the ground and deem it a catch, assuming at the point of the lunge. So its not make a football move while falling. It's making an act to interrupt the fall or gather that actually completes the catch process. But the ambiguous addition in the case plays of performing a lunge is present in all. Not one case plays refers to any other act. And this additional act is clearly not called out as part of the process. Why is that? What are they trying to communicate here by defining it that way?
You can question whether or not other things qualify other than a lunge. The case plays only refer to a lunge as being the act. I believe they chose lunge because it is the only act a runner can do. They could also protect themselves or ward off contact. That would also tie into them having the ability to gather themselves. A reach is an act anyone can do. You don't have to be a runner to reach. You can reach while in mid air. Can you protect or ward off contact while in mid air? Possibly. But far more of a judgement call.
The case plays do bring into question whether those specific scenarios only deal with players who have been forced into the ground via contact. The language is certainly in the case plays to suggest that.
A catch can be completed while on the ground. That is obvious. That is becoming a runner.
What's at question here is if a player can complete the catch while falling. The first part of this is a judgement call if the player is actually falling in the first place. If he is deemed to be falling, then IMO, the case plays elude to if the player can regain their balance or gather themselves enough to act as a runner and then perform the lunge ( the only act clearly defined as fulfilling this requirement ), then it becomes a catch and therefore does not require the player to maintain control through contacting the ground.
The determination on the Dez call was that he was clearly going to the ground and at NO point regained his balance or gathered himself in a demonstrable way PROCEEDING the "lunge" he made. And its even disputable that the action he made was a lunge, or a reach or all just a jumbled bunch of actions he made. But the key here is that it doesn't matter what "football" move he made. He never regained balance or gathered himself first.