OP, you need to address the open floor plan as well as addressing your speakers. Have you taken measurements of your in room frequency response yet? Can you post your system, pics, and your measurements in your virtual system in your profile (see mine for an example). I would not spend a nickel on speakers until you get the frequency response of your current setup as flat as possible.
I also use a Marantz processor and the new paid upgrade of Audyssey is a huge improvement over the one that comes with the unit. Don’t buy new speakers until you get the upgrade (and a calibrated mic) with your current system: