OK, so I'm not familiar with all the equipment you mention, including the Sundaras. The comments I am about to make are based on driving Audeze LCD4, LCD3, LCDxc which are full size planars and the LCDi3 IEM planars and the conventional Shure SE530 IEM and Sennheiser PMX686g sports.
My Astell and Kern AK70, and AK SP1000M are stellar, both have 2.5m balanced and 3.5mm single ended. The AK70 is so portable, great for anything active like running and snow skiing, the AK SP1000M does sound better, still pretty portable, but both do a great job through all my headphones and driving my top end Audiotech Fischer/Hertz car system.
I also have a Fiio M10 which is lovely, but shaded by the AK SP1000m, although I vaguely recall it was cheaper.
Even better is my Chord Mojo 2. It's a bargain I think for AU$900. But you'll need a DAP or phone to feed it a digital signal as it is only a DAC/Amp, so you have to carry two bits of hardware. But it sounds sublime. Truly sublime. Insanely good driving my car system, shits on my top end pioneer CD deck.
Re balanced vs single ended, my experience is that you get no/minimal SQ improvement from balanced unless you have interference problems which is why it is standard for pro gear. You do get more volume from balanced.
As always PLEASE do your own due diligence and have a listen yourself. Your taste may well differ from mine as may your perception of value.
PS one last thing, for desktop I can very strongly recommend what I have in my lounge, a Burson Conductor 3x, and Musical Fidelity X-Cans, both driven by a Cambridge Audio 840c CD player and a number of other sources. And I can also recommend the Sparkos Aries/Chord Qutest I have in my home office. But carrying around the desktop stuff between rooms at home is a complete pain in the ar*se. Let alone between home and work. For travel between work and home I'd go the best portable you can get, plus you have the added bonus of driving a car system with it.