Thank you for your suggestion. I own ES100, a predecessor of Qudelix 5K. I found it very convenient as an "around-the-neck BT receiver", because the intermediate connector of Sennheiser IE800 just fits into its 2.5mm jack and I can clip its tiny body on the collar of my shirt.Ignore SINAD and Bal vs not Bal, focus on output power and EQ capabilities.
The BTR7 will sound better than the G5, because it has more than enough power for your headphones and IEMs, plus the capability to correct the frequency response.
I'd choose the Qudelix 5K over the BTR7, because it has even better EQ and a much more complete software package, plus still more than enough power.
But I did not quite like the sound of ES100 in terms of clarity, crispness and power, even though I was able to fine-tune the equalizer curve. Fiio Q5s was better in these aspects, but the sound still appeared a bit muddy. I like the crisp sound of Topping D90 for my speaker system and am looking for a portable system that can provide similar sound. I thought that higher SINAD would give more faithful sound reproduction = clear and crispy, and balanced signals would give more power. Am I wrong?