Have you created "activities", ie "watch TV", etc.?
I have the Google mini and it works reasonably well...when I say "hey Google turn on watch tv" it does, etc.
It also will pause, lower/raise volume, etc. as well as "turn of tv".
If a device isn't listed you can try adding the device by using its' remote to talk directly with the Harmony remote. The Harmony site shows how to do it. Same with adding a control.
Good luck and keep us informed.
TV: Sony XBR 65X950G, AVR: Marantz SR5011, Speakers: front/Paradigm Prestige 15B bookshelf, center/Paradigm Prestige 45C, surround/Paradigm Atom, sub/SVS SB3000, DVD: LG UBK 90 UHD DVD Player, Media Player: Zidoo Z9S, Remote: Logitech Harmony Ultimate Home