With the latest iOS and macOS updates and features, I can Airplay2 from iOS to macOS.
macOS is connected to my RME ADI-2 DAC.
RME supply bitperfect test files, including 44.1kHz and 96kHz test files.
Airplay2 from iOS to macOS passes 16bit/44.1kHz
On macOS, in Audio MIDI if I (manually) change my DAC’s sample rate to 96kHz, interestingly, the 96kHz test file played from iOS to macOS also passes…
There is no cable between iOS and macOS. All over WiFi…
The most interesting thing here is that 96kHz sample rate test file is not being downsampled… otherwise the DAC screen would not show bit perfect test has passed 
Anyone with an RME ADI-2 can verify.