Audio support like atmos, alternate default launchers, maybe remote with full features like air mouse, play/pause, voice recognition etc
Most of what you're looking for as an "upgrade" to the Beelink GT King -- can be achieved by many TV boxes (including the Beelink GT King itself). Haha..
**
You want Dolby Atmos audio support -- but you never state what app(s) you use.
Do you use Kodi?
If you use Kodi, any decent Amlogic S9xx TV box + able to run CoreELEC OS -- will give you support for lots of HD audio formats (including Dolby Atmos audio).
(So) Many Web sites talk about Kodi + 4K HDR + support for various HD audio formats.
One starting point can be here:
https://forum.kodi.tv/showthread.php?tid=252916
But able to support -- DOESN'T MEAN guaranteed 100% good / smooth playback all the time.
If what you playback is extremely high bitrate (in both video & audio) -- then many TV boxes will struggle (to give you smooth playback) -- and you end up having to go back & buy the Nvidia Shield (because of the sheer power of its' hardware).
If you don't use Kodi, then Dolby Atmos audio support will also depend on the app you use -- not just depend on the TV box.
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There are so many launchers for TV boxes that you can choose (in 2021) --
without having to depend on TV box manufacturers to give you this:
https://troypoint.com/android-tv-launcher/https://www.maketecheasier.com/best-android-tv-launchers/https://byteswiki.com/best-launcher-for-android-tv-box.html
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Many TV boxes have multiple USB ports (including the Beelink GT King).
Just buy any decent air mouse -- plug-in the air mouse USB dongle to the TV box & you're done
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It's sad... but (unfortunately) many people do not understand that:
(Many)
TV box makers have known since years ago -- that the TV box market don't seems to have a bright/good future:
(1) For a small / mid size TV box maker -- it's extremely difficult to get a new TV box model to be 4K Netflix certified.
(Amazon / Nvidia / Xiaomi can get their TV boxes to be Netflix certified -- but this is difficult for the smaller TV box makers).
* Because
Netflix is DELIBERATELY VERY selective in what they do regarding Netflix certification.
* That's why many 4K TV boxes are actually Google certified running official Android TV OS -- but NOT Netflix certified.
*
Let's say you want to you make a good quality / highly decent TV box:
+ You give quality good performance hardware.
+ You invest heavily in software team to give good firmware upgrade support for the TV box.
+ You do a ton of R&D + ADD a lot of features / functions to the TV box.
After the new TV box model is produced, can you sell at a good price? Like S$150+ or S$200+ ??
Short answer:
NO! Why ?!?
BECAUSE nobody will buy a $150+ TV box without being 4K Netflix certified --
when a cheap S$60-S$80 Xiaomi Mi Box S TV box is already 4K Netflix certified !! Haha...
(2) More & more TVs are now running official Android TV OS + each year the hardware on new TV models gets better & better.
(2a) A new model 75" TV can easily sell for S$1xxx (or more) -- but
a new TV box at only S$150+ people already say the TV box is expensive !! Haha...
(2b) As TV hardware gets better...
In the coming years / future -- if the new TV already has 4GB/6GB RAM + 64GB/128GB storage + A7x range CPU + decent GPU + runs the latest Android TV OS -- why would people still want to buy another new TV box (to replace their old TV box) ?? Haha..
Now is Jun 2021, even Xiaomi has not released a new TV box model to replace the Mi Box S (for the international market) -- while the Mi Box S hardware is multiple years old / outdated already.
Why?? Because of above (1) & (2), can't make good money from selling TV boxes -- so (Xiaomi) just concentrate more on selling TVs better !! Haha..
Go & look at all the smaller (but decent) TV box makers: Minix, Beelink, Ugoos, Mecool, etc, etc.
Overall, as each year past by --
less (& less) new TV box models from all these smaller TV box markers.
Why?? Go see (1) & (2) above. Haha..