For sure wireless, with its own receiver (dont have one yet) to plug straight into TV, and Dolby 5.1/7/Atmos is available on TV so it would be great to have that in there. Since starting to use the Drop/Sennheiser HD 6XX's on my PC, it gonna suck going back to basics on my TV. Something with a similar sound profile to the HD 6XX (and price) is where I'd feel comfy.
Ok then, this is probably going to be a long post.
The Short Answer
I would say the most feasible option is just to plug your HD6XX straight into the TV and you're GtG. Especially if you're alone in the room while everyone is sleeping, there's little chance of people tripping over the cord.
I wager you aren't going to get wireless 5.1/7.1 audio into headphones, from the TV. If so, it would cost quite a bit of money.
The Long Answer
Wireless: For the mass majority of BT headphones/earbuds/IEMs, they will only transmit audio in stereo. There are a few that might provide virtual surround sound, but I don't have specific brands/models popping in my head right now. Most of them are fairly expensive, though, and probably not going to sound all that great through BT anyway. I recommend BT with LDAC support for the higher bandwidth and better audio but it STILL isn't going to sound "awesome" (but it will sound "good"). BT is a convenient option, but if you want actual high quality audio, I would stick with wired devices for now.
Atmos on TVs: I hate when TVs and cell phones proclaim "Atmos" as an audio setting. No, it's not. They licensed the name, but it's just a name and not the truth.
If it's not Atmos, then WTF is Atmos?
Atmos - true, real Atmos audio - is 5.1.2 or higher of actual, separate speakers set into an actual room. That would be five speakers (center, right and left speakers, then two satellite/surround speakers), a subwoofer (the ".1"), and overhead speakers (the ".2"). Atmos decodes an audio track into a unique variance that matches sound effects with speaker placement in a consumer's home theater setup. For example, I have 5.2.4 - center speaker, right/left, and two rear speakers, 2 subwoofers, and 4 overhead speakers. The overheads are positioned two slightly behind me, from the ceiling on my right and left, and two positioned near the middle of the room overhead right/left. But there are the receiver can be calibrated to match the way the speakers are positioned in a room: 7.1.2 for 4 surrounds and four overheads, positioned either behind, middle, or front of the room overhead depending on what someone wants to do... dozens of options. Atmos can allow up to a 64-speaker configuration (but most receivers usually only go up to 7.1.4, or 9.1.2 for home theater use).
Telephones are NOT real "Atmos". It's a gimmick namesake to make people think they have something special. Same goes with TVs. What these devices do is attempt to simulate the "fullness" and fill of surroundsound ("SS") from the TVs puny speakers. It's just a simulated effect that adds reverberation and tweaks certain frequencies to trick the ear into thinking there is more robustness to the sound. Thus, you have fake Atmos on phones and TVs, and most of these devices won't even be able to recognize/decode an actual Atmos audio codec.
SS Headphones:
This leads into 5.1 or 7.1 audio headphones. Most are simulated/fake. I bought a few headphones that actually had 5 speakers/drivers in them, and another that had 7 speakers in them to be "true" SS headphones. They all sounded like shit. To be honest, the best sounding SS headphones I ever owned where the Sennheiser PC363D (now discontinued, a new version is out now). They were stereo headphones with a dongle that did the simulated 7.1 audio. It was great. But the dongle broke within 6 months; I got a replacement under warranty, and THAT dongle broke after 3 months. After that, I've been using the SoundblasterX G5 and G6 for my virtual 7.1 audio, and they're really good. I would suggest just sticking with this route (a soundcard with virtual surround), since then you can plug any headphone you want into them and game with lots of variety.
What About SS with my Headphones on the LG C9?
I'm not sure how to get 5.1 or 7.1 audio straight from the TV into a pair of headphones. I don't think it's possible without spending a lot of money. For example,
Smyth Research has a virtual audio box that will do just that: Make your headphones sound just like speakers in a room, complete with head tracking so the sound changes when you shift your head. But that's not $400 lol
There is the
Audeze Mobius, and it goes for $399 before shipping. These are excellent headphones, and they ALSO do head tracking and virtual SS. However, it only does stereo audio through Bluetooth.
Alternatively, I am sure there are switch boxes or trasmitters that can take the HDMI out from the TV, shoot into the box and wirelessly connect to headphones.
In the end, I am sure your TV will down-convert audio streams into stereo. It should sound fine, since they most likely accommodate the audio output jack requirements to play DTS, DTS-HD, Atmos, AC3, DTS: X, etc... down into a stereo format for just such occasions.
But Kc, I want SS in my headphones from the TV!
I would wager there are devices out there which can provide a link from HDMI to simulated SS, but I DOUBT through Bluetooth. I haven't looked into it.