Preferred Audio Formats in iOS?

I am going to be using AVAudioPlayer to play sound effects and looping music in a game. I haven’t been able to find any recent discussion of what format to use (given I almost certainly need to compress it). https://developer.apple.com/library/archive/documentation/AudioVideo/Conceptual/MultimediaPG/UsingAudio/UsingAudio.html#//apple_ref/doc/uid/TP40009767-CH2-SW28 is deprecated (and talks about “AAC” but afconvert -hf shows at least 7 different formats that can be saved in a CAF).

Has that guide been updated? Does hardware vs software playback still matter in iOS 9+?

I’m not really worried about performance in terms of impacting frame rate.