Read third post down from KBK...great explanation.
https://www.stereophile.com/content/balanced-xlr-vs-unbalanced-rca-1
The fact that the Marantz units and your sources are not fully balanced means you will likely experience minimal gains vs. single ended connections. in fact, there are occasion where you will find the single ended connections may sound better. I can't speak about those explicit units, bit I have an amp where the single ended connections definitely are better than the balanced.
https://www.stereophile.com/content/balanced-xlr-vs-unbalanced-rca-1
The fact that the Marantz units and your sources are not fully balanced means you will likely experience minimal gains vs. single ended connections. in fact, there are occasion where you will find the single ended connections may sound better. I can't speak about those explicit units, bit I have an amp where the single ended connections definitely are better than the balanced.