Run your sources into the preamp in 1080p. 80% of people can't tell the difference between 1080p and 4k, also when you stream 4k content you aren't getting that resolution nor HD audio because its compressed.
On a side note, your SSP and the Anthem D2V are still ones at the top best sounding surround preamps. When you replace it, take a look at the Anthem AVM 90. In my opinion it bests yours and the D2V but not by a wide margin. The AVM 70 would be a lateral move sonically but get you all the newest technology.