Every Orbi satellite will connect to your existing Orbi system, and any Orbi satellite will function in and certainly cover a two car garage as long as it can make a connection to the Orbi that is closest to it in the house. That is the key. If a smart phone or tablet can connect to the house system from any point inside the garage on a 5G channel, you are "good to go."
The "proof" is when you sync a new satellite (inside, in the same room with the Orbi router so you can watch what happens and look at the Orbi web interface all at once), then move it to the garage and see that ring light on the top turn BLUE for two minutes.
