Just want to get this right and start looking forward to pure enjoyment

Very sensitive topic as music means so so much to me. Putting chromecast aside, is there any solution out there that would match my desire here? To be able to pick up a tablet and use musicbee as my player that will stream content direct from NAS to my receiver? I see there is a subsonic plugin, and subsonic supports chromecast.but I'm still getting the impression that on the tablet I would have to use Dsub or some kind of subsonic related app rather than musicbee itself? I know there is the UPnP trick to be able to stream to my chromecast - but would that be a direct NAS to chromecast stream? Or would it be first going through my tablet and then to the chromecast? And would I actually be using MB on the tablet or would I have to use the UPnP interface? Managing my music is one thing - but the issue I'm coming with today is the ability to use it as my player. I'm well confused about renderer, controller, library etc. The dream would be to have MB on a tablet and be able to stream directly from NAS to chromecast - but I see this isn't so easy (if not impossible because I don't understand how the various software interact).

The problem I'm having is that plex just doesn't have the look and feel i'm going for. Thing is I never sit at my PC, so the interface (controller) I'll be using in the living room is my phone or rather, a future tablet purchase. So I recently set up a synology NAS - put plex on that and my android phone and I also got a chromecast audio that I can stream easily to. You'll quickly see that I know little of what I'm talking about but I promise I'm trying to understand, every day! Kind of ready to rip my hair out with confusion though

Plex media server synology