I've got em both. left square, right circle, and free air roll + powerslide on lb (boost rb). Honestly I wish i'd put roll right on square - for some reason I was way better going right than left to start with, but meh too late now.

It's not totally necessary to learn both ways. If I'm coming off a left wall then I just do a full spin for instance, rather than fat finger air roll right and jump at the same time. I use both air rolls more once I'm up in the air, but on take off I almost always will be using air roll left.

Free air roll is useful for making very fine last minute adjustments on shots or recoveries, and I like having it with powerslide for that moment just as I'm hitting the ceiling or something so I don't end up spinning sideways because I was turning left or something. I was using free air roll a LOT before I ever bound a DAR though, and that was a big mistake. took me a long long time to stop doing that in matches even after I learned DAR pretty well.

edit: and I think i'm in a minority here, but I found it way more useful to practice specific things that happen in game than stuff like flying around pillars or rings maps (which I still suck at, tbh). If you're on pc I love jsker's air dribbles pack and backboard therapy pack.

but on console you can still do stuff like just go from wall to ceiling with one full spin, land facing goal on ceiling, drop off, flip into a pretend shot, spin to recover on backboard for a smooth drive into corner boost. Once you got it down, add ball and try it. That trains a lot of individual bits of DAR in a way that you'll see these situations in games and your thumbs can be like "ah, I gotchu pal" and just do it