Mpdahl, are you happy with the new setup? If so, don’t read any further, if not consider my comments below. Also, it maybe too late to do anything so if that’s the case consider it nonsense reading :).
What bothers me here is that you said that you prefer the sounds of your old Marantz twice. Personally, I would never buy audio equipment that I’m not satisfied especially compared to my previous component. Is the Marantz broken? I haven’t heard a Peachtree in a while, but I never enjoyed class D amps. I suspect you like your Marantz more partially because it’s a class A/B amp. A few years ago, I looked at Peachtree, Rogue Audio and a few others and honestly for the price and what was included I wanted to love the Peachtree but I ended buying the Rogue Audio Cronus Magnum 2 with a standalone DAC. For the sound quality was night and day. You’ve spent a lot of money, don’t settle for something your not completely happy with. Not sure about the return policy of your Peachtree but you could consider a cheaper option which maybe a better choice for you and your wife is to get yourself the Bluesound Node 2. It’s a very capable music streamer with a built-in DAC. You can connect this to your Marantz. Your wife could stream and use her iPhone to the Bluesound and from the saving buy yourself a Tidal music subscription for you and your wife, if you don’t have one already. Possible option 2, return the Peachtree and consider different integrated. Again, if your happy disregard. Good Luck and Happy listening.