Funny you mentioned eARC, My tv is new nothing fancy or even high end but it's good Hisense. When fired everything up, ran though setup, was going through everything, the last thing I tested was TV audio return back to AVR, had no audio at all nothing. Went umm, went back into audio settings in tv, did a audio reset back to when it came out the box. Turn everything off. Powered everything on with tv remote, once everything was dailed in, AVR had audio from tv. Audio the only thing I'm guessing here is the tv didn't recognize or glitch ARC to AVR. Maybe do a rest for audio and or for HDMI in settings in your tv? Check in settings on your AVR make sure HDMI Control is set to on, ARC set to on and Standby Sync is set to Auto.
Also check make sure in settings on your AVR, that HDMI Out 1, is set to Control Sync. That is what mine is set to. I also have HDMI Out 2 set to on.