Airplay doesn't do 24bit audio.
I think you're overthinking all this a bit, firstly you don't "need" 112+dB as human ears can't hear that amount of dynamic range and there's no recordings out there with that amount of dynamic range either.
It is also unlikely you'll be getting anywhere near that amount of dynamic range out of any HiFiBerry board, the top-measuring HAT-based DAC you can get (Allo Katana) has been measured at 109dB SINAD (Signal over noise and distortion).
If you want measured performance use a standalone/separate DAC not a HAT board but as always, measurements don't tell you how something sounds, just use your ears.
Looking at the spec sheet for your board the THD+N is -93dB so the most DR your HiFiBerry will achieve above thd+noise is around 93dB which is still beyond the range of your ears.
I think you're overthinking all this a bit, firstly you don't "need" 112+dB as human ears can't hear that amount of dynamic range and there's no recordings out there with that amount of dynamic range either.
It is also unlikely you'll be getting anywhere near that amount of dynamic range out of any HiFiBerry board, the top-measuring HAT-based DAC you can get (Allo Katana) has been measured at 109dB SINAD (Signal over noise and distortion).
If you want measured performance use a standalone/separate DAC not a HAT board but as always, measurements don't tell you how something sounds, just use your ears.
Looking at the spec sheet for your board the THD+N is -93dB so the most DR your HiFiBerry will achieve above thd+noise is around 93dB which is still beyond the range of your ears.
