Read up on homebridge. This is what allows non-HomeKit certified devices (like Hubitat) to be brought into the apple Home app.
There are a number of ways to set it up, but essentially it runs on an always-on PC (or NAS, RPi, etc.).
Then you need an integration between homebridge and Hubitat, there are two popular community apps that can do this (look here or here).
You can ignore home assistant for this goal.
