Marantz fan here too. I have owned 4 or 5 of them. I switched for a while and came back
I vote no 7.1 unless that is Atmos not a traditional 7.1 setup. That is the setup I currently have and it works well. I had a 6.1 setup previously and Atmos is much more worth it.
Though my setup tends to be use for HT a lot these days, my focus was always music from the beginning. Start with the mains (including taking the center into consideration) - get something you like for music and let that drive the rest of the conversation. That benefits you in two ways: 1) you will always enjoy your music 2) HT only benefits from it since good speakers that you like the sound of will always sound good for HT as well.