Even if the atmos for headphones isnt using the object data(the stmos track instead of the 7.1) it's still probably doing some upmixing, 7.1 to 14.1, and while not discrete data, it can often effectively stear certain effects to height channels or make effects sound bigger/roomier, etc
The term is AVR, audio video receiver, or a pre/pro, an audio processor snd pre-amplifier.
Dolby Headphone has some room emulation(i.e. reverb) that I don't think atmos for headphones have, that's probably what your hearing.
First about AVR, I know there is more than one type of "advanced audio equipment". For example, there's one special piece of equipment specific to Dolby 5.1 Laser Discs which takes an analog sound groove which replaces the right analog audio track, but is encoded and makes no sense without the decoder, called AC3 RF, and converts that into Dolby Digital 5.1, the exact same standard used in DVDs, with the Toslink or Coaxial output. And yes, if you run this through the middle, in between the LD player and the Headphones, Dolby 5.1 Laser Discs will sound like Dolby 5.1 DVDs, even through Turtle Beach headsets, and Laser Disc is older technology that had a few hacks since 1978.
I knows there's processors, pre amps, (though I wouldn't use those terms until prompted and don't quite understand the difference) and combo units, All I know is that surround sound is an expensive hobby to get into, even if half-assing it. And my long time offline friend and neighbor, Jamal "Zophar321" Nickens, who competed on 2 nationally cable-televised video game game shows/realty shows where the goal was to find the best all-around player, and Triton Gaming Headsets was a sponsor of the second one he was in. I asked him if he could accurately pinpoint direction of sounds in there. And he said yes. I asked if it will work for movies, he didn't know.
Isn't the whole reason to get surround sound equipment is to hear everything all around you? If the answer is yes, (and apparently, some people might disagree) then the equipment that can covey direction best is the better choice for a surround sound? Right?
I find the Turtle Beaches good movie watching sets (assuming your device can convert DTS to Dolby), but I was able to do things with audio information that helped me intercept the "Apple Juice Boss" in Sonic Lost World, and I dodged Goblin clubs in Breath of the Wild by hearing both where and when they were striking from when running away and they were off-screen behind the camera. And BOTW doesn't use a proper Dolby or DTS track. It has a specially mixed headphone track that sounds 3D. It may not sound subtle, but it gets results
And I know enough to know LCPM 5.1 does NOT fit along Toslink bandwidths. Therefore, if my headphone gets surround sound from a DTS 7.1 movie on my Xbox One S, the only input is Toslink, and LCPM doesn't fit beyond 2.0 along Toslink, then an Xbox One converts DTS into Dolby before sending it down the Tolsink line.
And yes, in Turtle Beach promotional videos, they say they use reverb to simulate 3D with 2 headphone speakers. As to why there was no room emulation in Dolby Atmos Headphone app, what's the point of that? Isn't the whole point of Dolby Atmos Headphones to hear in 3 dimensions?