I have looked into this previously and as far as I can tell, the answer is no. If you were on Windows, the answer would be: another iPod. Unfortunately, though the iPod connectivity feature is presented in MC for Mac, it doesn't actually work. It is frustratingly close to working - it moves files to your device, but not to correct directories for playback. Feature should be removed from Mac MC, i don't expect it will ever be fixed.
A great answer would be a dedicated Android app for JRiver, then you can use your Android-based device of choice. Looking around forum, there seems to be no movement in that direction. They are plenty of nice music apps on Android, and on Windows you can sync playlists or least copy playlists - i don't think even on Windows there are any players that send back playcount (a really an important feature to me) save one I know of (see below). But, since macOS has no MTP (Android's current way of connecting to a PC) support enabled, you can't even get an Android to mount in the Finder, let alone in Media Center. There are various Terminal-based approaches to mount Androids, but I have had no consistent luck with any.
DoubleTwist allows you to sync Android to iTunes, but that's iTunes. So does the pricier SyncMate, supposedly, which also lets you mount Android as hard drive in Finder, and may possibly also allow you to see an Android in a third party app like JRiver, but when I tried finding out about third party app support a while back SyncMate developer could not confirm and they do NOT have a trial version of their full software to allow users to see what works. I recently tried running their limited free version, just to see if it could even see my phone, and it wouldn't even launch. And they want good money for the paid version.
There is a cloud based solution that will sync playlilst and counts: Gizmo, a JRiver application for Android. But you have to keep your Mac on and running JRiver as server whenever you want access and your portable player has to be connected to internet and files are transcoded for playback. It does work quite well for what it is, but it is a streaming program, not what you are looking for really. It is a free app, so you can try it - but maybe you already are aware of it. I personally would be very happy if Rocket Player or Poweramp, two Android players I like, could sync playcounts to Android & mount on a Mac. But I think playcount synching is missing from Android in general. Only thing I know of that works, on Windows (not Mac) is to use MediaMonkey on your PC and run their MediaMonkey Android app on a portable. That's all I know of. I would love it if JRiver could offer a similar solution, but even so it would seem likely to exclude MacOS.