Wow ok I thought rca can be configured to output to put a smile on my mono blockSee pp19-20 in the WiiM Amp manual which refers to bluetooth out (kind of essential for headphone use) and airplay cast which the Pro and Pro Plus have. Also, if the Amp DAC has digital filters, that's where I would expect to see them. The app currently doesn't have an Audio Output menu at all to configure those options.
I'm not expecting any more than that.