I don’t think it’s the preferred codec on account of improved SQ, it’s just better optimized. You get technicalities comparable to LDAC (unless one really needs all of that good music they hear between 24 and 48 kHz ahem ahem) but with a data transfer rate comparable to plain aptX. And it will prioritize stability, which is a wise choice since audio cutting because a bit rate target could not be met is way worse than a short, mostly imperceptible dip.
The good people at Qudelix mentioned while they were with Radsone how the different codecs do not sound differently per se, but since there’s a lot of processing involved good engineers will implement each codec in a specific way. In my experience, since engineers know very well what kind of people are turned on by LDAC (and I myself do like that it’s there!), they tune that for clarity and audiophile detail, with a focus on upper mids and treble.
The various aptX flavors are bassier, more mainstream in a sense. In fact aptX Adaptive, like aptX HD, sounds like high-end mainstream - bassy, punchy, fun, but with more texture and detail than unrefined crap designed to appeal to people who only know Beats-like boom bass.
I personally like aptX Adaptive a bit better, it matches IMR iems very well, where LDAC is great for balanced armature analytical gear.
I turn the volume up a notch on aptX Adaptive vs LDAC, not sure if it’s a gain thing or the warmer tuning.