Just want to leave a reference link here for future users coming to this thread.
There is a (custom) integration to use Hubitat’s Maker API to talk/control devices that are tied to Hubitat - main application is to use Hubatat hub as the radio for zigbee and z-wave.
… other than zigbee and z-wave, you likely could integrate your gadgets directly to HA, and then use HA as frontend & automation engine that ties everything together.