Yonomi helps immensely... however you do ave the same issue described above... The harmony hub is truly "blind" to the actual status of the TV, or any other device. It takes setting up the system and relying on it solely, unless you have someone or the ability to help correct things if they get out of sync... say you turn off the TV, then tell Alexa to turn off everything through Yonomi or directly to the hub... it will switch the TV power to the status it "isn't" currently. Once out of sync, one must go into the Harmony app and correct it to get things back on track. Some kind of hub is required. The newer the TV and other Audio/video devices, the better things work as well.
Once a Routine is set up in Yonomi, Alexa just talks to Yonomi app, and it talks to the hub for you, allowing commands that are different, instead of "Alexa, Tell Harmony to turn on a Movie", it can be named whatever you want such as "Alexa, Turn on Movie".... Much shorter commands and less complex. The hub is just a cool remote that uses an app through your chosen variety of Smart phone. Yonomi simplifies the commands... Alexa doesn't care what the commands are either... whether you tell it to tell Harmony to do stuff, or whether you tell it to do those same things directly...
It takes some careful consideration to get things set up where it works flawlessly, as the Human factor is actually quite a problem in being exacting in the commands... Took me a week to figure out where I was screwing up commands to turn on a movie, while I could easily get "Alexa, turn everything off" to work perfectly. Once I learned the correct command for the movie to turn on... I have control and never turn on anything in my A/V system by actual remote with anything other than the echo.