More than likely the new smart remotes will accept that model of the Marantz and if not you can download the specifications for the Marantz from the remotes website and upload it to your smart remote... But those remotes that do that can be 2 or $300
Best bet is to either get a universal remote. Not sure if Best buy would carry this specific remote. Another option would be to get the Maratz app on ur phone and control the receiver if it supports network or Bluetooth capability
I do not have much knowledge on this
Thanks! Your answer is awaiting moderation.