The Harmony actually uses Routines to start whatever function you'd like when set up properly... such as "turn on TV" or "Turn on Fire TV", "Watch a Movie", "Turn on Playstation" Turning on the proper items and the TV when required and tuning to the proper input for that function... pretty cool and worth the price if you buy a refurb (I' seen them as low as 59 dollars lately).
Echo will work with Harmony hub to adjust Volume, Change channels on the Set top boxes of most services and a regular Antenna input as well. There is a LOT of functionality I don't use on it, but the ability is there. Depending on your needs It may be just the device. May not be. Read a bunch and make that decision based on YOUR findings and needs.