You mention that using Harmony didn’t work for you since you can connect to only one hub at a time.
If you only want limited control (turn on an activity), Hubitat has a great integration that would allow you to connect multiple hubs.
In my setup, I have 3 Harmony hubs and they are all linked to Hubitat. I can turn on or off any device via voice command or the dashboard. I have also setup some basic commands that I need to run on occasion for some of my activities (Play, Pause, Stop). I set that up via voice commands and some custom Alexa routines that set values on a Virtual dimmer. A rule converts the dimmer values to specific Hubitat/Harmony commands.
