I need an HDMI splitter for Apple TV 4K

I cannot switch to 4K video when running through my Marantz receiver. The Apple TV 4K indicated there is an issue. Works with the same cable when connected direct to the LG TV and switches to 4K. BUT, there is no other audio out and the receiver does not support bluetooth connections. When trying an HDMI splitter, video format switches back to 1080p. Is there a splitter that will break out audio which I can send to my receiver since Apple has removed the digital out for audio in this next gen version of Apple TV?