I have connected by DX160 (2020 version) to several outboard DACs without any issues. My own Elite SC-79 AVR and Elite A9 both work (although the A9 is limited to 16bit/48kHz). I have also connected to some TEAC devices and the output is fantastic.
Following up on this. I have verified on another USB DAC device, a TEAC UD-505X. Everything worked as expected, with the display of the DAC clearly changing to match the format of each file that was being played on the DX160.
A note of caution however. The player app will influence the output, based on what is supported and also depending on the settings in that app. I have tried these four apps with very different results.
1.Neutron, set to "Bit Perfect" followed the source frequency of each file. The only exception I found was with some DSD files, but I'm thinking this was something I changed in the settings that I couldn't figure out quickly. Otherwise FLAC, ALAC, and even lowly mp3 files all played with exactly the format in question. The DAC does all the heavy lifting in this case.
[This is the app I would recommend to use when using an external DAC]
2. Foobar2000, all files played back natively up to a limit of 96kHz. Everything I have that was higher than that rate was down-sampled. So work is split between the app, and the DAC.
3. Poweramp is an odd duck. The dev does not want to support having anything follow the source frequency at this time. So for hi-res you need to select the sample rate manually. Poweramp will then up or downsample everything to be played at that rate only. So lots of CPU power being used in the DX160 for any sample rates selected that don't match the file being played.
4. GoneMAD doesn't currently use a proprietary audio engine, so all output from this app is limited to the 48kHz max stock Android limit.
I don't use the stock iBasso Mango Player, I just can't get the browser interface to play nicely like all of the others do with my library. And it takes a very long time to update any time I do a library update on the SD card. So I can't comment on how well it works with external DACs.