The system is for movies/youtube only, I've got media player with optical out, but don’t want to use it in this system.

My source is Apple TV 4K gen 2 + Infuse player. Volume control with Apple remote (learned it from MSR+).

My TV is LG 83 C1, from the manual it can output 5.1 via optical out.

[Linked Image from forum.ixbt.com]

HD621 , 800v4, 861v4, DSP7000, DSP5200HC