I have an original Poly Mojo setup, and for the most part, I use these with Beyerdynamic T5p in a single location. It’s is a great headphone setup, but the Poly is far from perfect, and I wouldn’t recommend it.
Moreover, I doubt you will gain anything by adding an alternative headphone amp and DAC. Maybe get a Roon Ready network streamer, so you’re not tied to the laptop. But do your homework as few streamers have USB outputs. The FiiO SR11 is a good option.
Finally, note that Chord do not used balanced outputs (a design decision), so be mindful of this when buying other items. I don’t recognize the USB cable, but you don’t need anything other than a basic USB cable that costs a few quid – avoid “audio” and “boutique” cables.