You are welcome!
This is true that you can use a hotspot, but this means that all you are sharing is the WiFi. You would only need to use UPNP/DLNA if you are trying to stream music stored elsewhere in your local network to your DX160 (i.e. a NAS drive or something like that). If you are just using something like Tidal, Amazon, Spotify, Apple Music, etc... you just need to share the WiFi connection to your DX160. At home, you could use your home network to the DX160 to the Mojo 2. There really is no need to use your phone except when out of WiFi range at home, then only for hotspot sharing.
The Coaxial connection will send it as bit perfect as long as it fits into 24/384, or DSD256. If it is higher quality than that, then it will down sample. This goes the same for USB out as well. But, once again I am saying that it isn't the connection that decides bit perfect or not, it is the music app that you are using... UAPP, Mango, Neutron, etc... will playback bit perfect (as long as you have it set to play that way with no DSP) from LO, coax, or USB-C. The difference between the connections is that USB-C, and coax are both digital and bypass the onboard DAC chips and amplifier both. The LO will use the DX160 DAC chips, but will bypass the amplifier (well, technically it doesn't truly, but that is another conversation altogether).