The unit has connections for controlled output - i.e. powered speakers (that's how I have it in the office) and fixed volume for recording or as a sound source for controllable power amplifiers (that's how we have it in the music room). If I understand your plan correctly, the sound from the TV is to be delivered to an INPUT of the WXC-50 and then controlled via the volume control on the unit or the MusicCast app. The plan went.

According to the data sheet of the TV mentioned, the optical output is available for sound.
The crux, however, lies in the interaction: is the sound on the optical output influenced by the TV volume control? The operating instructions may provide information.
If YES, it is always a back-and-forth between the controls of the devices; if NO, it would then be wise to control the volume only via the WXC-50 and to mute the TV.
This leaves the TV remote for the TV's "channels" and sources and the WXC-50 remote or MusicCast control for volume and sound source.