best thing would be to try yourself. if you have a chance to compare a higher and dap to yours.
my 2 cents: a transport shouldnt play an audible role in such setup, as its just reading and sending the ones and zeros to the next device. a zero is always a zero and a one is a one. but im sure there will be people telling that it indeed will make a difference. people on this forum also have the ability to hear differences between sd cards, so who am i, just trusting physics?...if you are into esotherics, snake oil, astrology, homeopathy, Qanon, UFOs or any of the likes, you might want take a look into the watercooler thread tho
someone in the 340 thread told me, the amp in the d16 is more sophisticated.
twister6 wrote in his review:
"DX340/amp15 soundstage is pretty wide but in a natural way, while it felt like D16 was stretching a little wider, giving you a more 3D holographic positioning of sounds."