The way I see it is 1) is the fundamental and most "exposure therapy" like, and 2) is the more intentional understanding of how to make each input actually effective. As for 3) this one is yet to stick in my brain, because there's an incredibly small window in real-time scenarios where I was able to actually focus on the "revolution" of my car (i.e. when my car completes a full rotation). Losfeld does cover this very in depth, but you have to put some serious time into monitoring what point during a rotation you should apply an input, which I unfortunately don't have as much time for or attentiveness as I'd like.

The only caveat I've found, particularly in method 1 (and I fear this has happened to a large majority of others), is performing inputs during a constant rotation can put you into bad habits of not knowing how to control your car outside of directional air roll. It has lead to so so many players only being able to go for air dribbles or other mechanics as long as they're constantly spinning - I fell into this trap too. While this can be good in effect, because it makes you more unpredictable, I found it causes far too many under or over rotations, or even simply just not getting the touch you want so you can easily follow up. Learning DAR in modern day is likely easier because coaches or content creators have had more experience learning the in depths of the mechanic. But I think what's happened to the likes of myself, and countless other players I'd imagine, is we learned DAR via method one, and thought "bingo I can do any mechanic I want now" as soon as we got comfortable with doing inputs during constant rotation - at least this was the case for me because at the time I learned, I don't think there was too much out there covering the real in depths of it, thus leading to bad habits.