Like I said I only have Fox Sports app through Fubo on the Apple TV and while various other apps on Apple TV can transmit Dolby Atmos, Fubo is only Stereo. My information is from the various press releases on what they are doing but I did recheck and the the Fox Source claims only DD 5.1.
I also discovered that Fox Sports used HLG form of HDR, not HDR10 or Dolby Vision. So some apps for streaming got SDR even though a few services got HLG HDR. Most home streaming boxes do not support HLG. DV and HDR10, HDR10+ rely on brightness to be of benefit, but HLG I believe is color range dynamics. HDR10+, etc. has particular advantage when there are various scene changes in a movie or TV show. A sports event doesn't have scene changes like TV shows or movies.
I think it is safe to make a general statement on what is and isn't, that Fox Sports is "experimenting." They are making changes with each broadcast, so what you see today may be different than what you saw last week. eg. They announced using 1080P cameras upconverted to 4K for transmission. But at least one sports event used 8K cameras in a joint venture with Sony. No need to get panties in a twist as to what is and isn't while they are experimenting.