So you see clipping indications turning the signal path star red, right?
If so, -3dB only reduces occurrences and you need to decrease the value more until completely free from clipping - download my test file for proper full spectrum 0dB signal evaluation without ambiguities.
Wait … looking at the specs of your devices now, I see the Marantz input sensitivity as only 200 mV, unfortunately without specification on it‘s overload margin so not sure about max possible input level without analog clipping.
The Holo on the other hand actually puts out 2.9V RMS single ended which could possibly cause analog overload.
In this scenario you‘d get analog input clipping and your signal path star, when enabled, would never turn red, but reducing headroom also remedies that by reducing Holo‘s output.
All that said and looking at your signal path screenshot, I have no explanation for other digital sources not causing clipping occurrences.
BTW, you’re actually only using half of the circuitry and sacrifice ultimate performance of your Holo ladder DAC and analog output stage by only being able to connect single ended to the Marantz.
Good luck in getting your issue understood and corrected.