I have a Roku on four TVs and Apple Airplay worked fine on all of them. It appears that with the Build 4193-CR update to my Roku Express 4k+ (3941X) on 4 May 2022, I lost the ability to play the Airplay streamed audio on my TV; the video mirrors fine but the audio will only come from my Apple device. The Roku Express 4k+ (3941X) is connected to my large screen TV and I have successfully used the Airplay feature to screen mirror from my iPhone, iPad, MacBook to the TV literally more than a hundred time over the past few years.
Note 7 Sep: the sound worked today when I did an AirPlay to my Roku equipped TV. I have attempted it numerous times in the past month with no success.