Hisense 65QD6N is a 65" 4K QLED Smart Google TV.
There were a few setup complications.
1) Remote control cover
The remote back piece has a down arrow; and yes the entire back cover is one piece and hard to open.
Try to use finger nail to poke into the IR spot so the cover will slide down a bit so easer to slide open.
2) Apple TV 4K
Plugged in to HDMI 1 initially and black screen.
Changed cable and switched to HDMI 3 (eARC/ARC) still didn't work.
But after a few more plug/unplug and power ON/OFF, eventually Apple TV 4K showed video configuration option and suddenly all workings.
Then changing back to the previous cable and HDMI 1 worked.
(Second time having some difficulty when switching Apple TV to a different TV. Maybe the problem is Apple TV and not TV itself.)
3) Vizio Soundbar with optical cable connection
Setup > Sound > Digital Audio Output is greyed out but the soundbar audio level light is ON and based off TV level, yet the entire soundbar system is not work.
Changing the sequence to turn on TV or soundbar first didn't help.
To enable soundbar, Setup > All Settings > Display & Sound > Audio Output, then switch from TV Speaker to OPTICAL (S/PDIF) then the soundbar will be working. And Setup > Sound > Digital Audio Output with additional options are enabled.
Unfortunately, there can be only 1 audio output so need to go into the menu to make the switch if not using the soundbar all the times.
4) Ethernet
If using RJ-45, it would be good to turn off Wi-FI and Scanning always available.
5) Device Power Off
Setup > All Settings > Channels & Inputs > External Inputs, there are options:
Device auto power off
TV auto power on
TV auto power off