You've got yourself all twisted up over this.
No ones saying it's a headphone dac,
This all stemmed from the fact that the output impedance is so low at .042ohms (maybe? from 20hz to 20khz that wasn't confirmed) and with 3v output, it's very capable of driving headphones to a decent level, even better than some tube headphone amps can.
Cheers George
Chord deliberately differentiated the 2Qute and Hugo, to fit into two different slots in their product line - the Hugo was a dac plus headphone amp (even if amp is rather a misnomer), and the 2Qute was the Hugo minus the battery and headphone amp, but with galvanic isolation on the usb input.
Chord have followed a similar policy with the Hugo2 and Qutest, so the initial Qutest design use cases, and product requirements will
not have included the statement 'the product shall be able to direct drive headphones'.
You are always free to buy a Qutest, and discover whether using the Qutest outside its design space, by direct driving headphones is possible.
In the meantime you are building a reputation like another frequent poster on the chord threads, who recently was (humourously?) described as 'will endlessly debate the merits of eating soup with a fork'.
You expressed surprise that the Qutest output impedence is so low at 0.042 ohms, but that value will not have surprised long-term readers of the chord threads. The Mojo value is 0.075 ohms, and the Hugo 2 is 0.025 ohms.
You may enjoy this
post from nearly two years ago.