Devialet Mania kept getting disconnected from AppleTV after about 5-10 minutes?

I am using AppleTV 4K gen1 ( with accelerator siri remote ) and Devialet Mania. It sounds great and the sonic experience is very nice especially with Apple Music and even watching TV+ movies with Dolby Digital 5.1. The only problem is that it disconnects after about 5 minutes.

I've thru Devialet support to 1) ensure latest fw 2) reset 3) ensure its on 5Ghz wifi network.

With Apple Support we have also 1) 18.2 tvOS 2) reset AppleTV 3) went thru settings via support screen share 4) change HDMI cable and change device HDMI port. I even tried w/o hdmi cable and still don't make any improvement.

This happens with either TV.app, Netflix, Hulu, or youtube etc., so it's not app specific.

This behavior exists since last year's tvOS-Mania fw. Both have done updates since and disconnects continue.

Is there any other AppleTV-Mania users out there with same experience?

Thanks much!

j