There was a bug with Trueplay that was supposed to be fixed, but users are still having issues with the Sub and surround levels. 

Try resetting everything and do the setup again. This time do the Basic Trueplay to see if that makes a difference. If you are happy you can stop there, or you can then try Advanced Trueplay to see if it works.

I’m not sure what “doesn’t work” means.

i recommend disconnecting all HDMI cables from the TV and powering down ARC and TV for at least two minutes. Allow the TV and ARC to reboot before connecting the HDMI cables between ARC and the TV’s HDMI-eARC jack. Now you can connect other HDMI cables to the TV, if any.