You asked if there were any other recommendations.
Yes, it looks like you are running everything through your AVR. I was too. I was running a Yamaha Aventage 3050. The 3050 was preamp output to a pair of monstrous Aragon dual mono amps. I figured I had it made. You have a Marantz- nice unit. My AVR is a flagship unit as well.
I had, off and on, read and ignored that a 2 channel integrated or 2 channel pre and amp will offer superior performance.
I was preparing to move and those two 75lb amps plagued my thoughts, I decided to sell them and buy a 2 channel integrated with Home Theater bypass, which allows the AVR to control the volume during video sessions.
I chose a Cambridge Azur 851A because it’s well reviewed and pretty inexpensive. I thought I could check the truth of what I thought of as the 2 channel myth. If it wasn’t all that different I could sell it and go back to external amps.
The results were eye opening/ear opening- stunning. The sound is infinitely more dynamic. Everything is elevated. You can file this away as you see fit but the longer you delay the longer your audio sources sound half as good as they could.