I have no advice to offer vis-a-vis setting up Home Assistant because there are many options of platform and z-radio hardware. Personally, I use a Home Assistant Yellow which has a built-in zigbee radio.
You can integrate sensors and other devices paired to Home Assistant with Hubitat using the Hubitat app "Home Assistant Device Bridge", a major contribution from @ymerj, @tomw, @ogiewon, and others. Here's the link:
