If you care about hi-res signals making it to your receiver without other devices tampering with them on their way to it, you will want a wired connection from the Mac to the receiver. Your DAC and Apple TV 4Ks support 48/24 but not 192/24 from hi-res tracks. Newer Macs support 192/24 multichannel over HDMI. They can Airplay Lossless 44.1/16.
Oh, and the projector here does not support 4K HDR @60Hz. If you want HDR from the Apple TV 4K, you will need to set it to output 4K HDR @30Hz 10 bit. With both Apple TV 4Ks connected to the receiver, make sure HDMI-CEC is disabled in every device. If the projector is connected to the Yamaha's HDMI OUT #1, make sure HDMI Link is OFF in the projector as well.