Arc sound always starts from Zero when I turn on LG TV

This may not be your issue but…
 

I've got a LG C9 and I'm pretty sure that's a function of the LG’s sound out settings (HDMI ARC). Changing the settings (Passthrough vs Automatic and eARC on vs off) seemingly affects the delay of the incoming signal that actually activates the Arc. Waiting a few seconds usually results in sound eventually.