If you have local media you can install Plex server on any PC(Windows, Mac Linux) and check out the Plex interface on any PC(Windows, Mac, Linux, including the one the server is on)
If you only want to stream and don't have any local media then as mentioned Plex isn't for you.
Now you mentioned Atmos. You are not getting Dolby True HD Atmos (lossless) with any of the streaming services, it is DD+. It will be Atmos but compressed and not at the same quality as the BD. If that matters then you might want to look into setting up a local library. To go deeper into the weeds, a Windows PC and Shield are the ONLY devices (minus dedicated BD players and boxes like Kalied$cope) that will let you bitstream Dolby True HD.
Do you have a theater room with a projector?