poor signal

Have you tried opening the garage door?  Depending on the construction of your garage or something in your house.  There might be something preventing the signal from reaching inside of your garage.  WiFi, circuit breaker panel, high wattage appliances, concrete walls, and so maany more potential sources of interference exist that people use every day.  Depending on the band that 5G signal is deployed on, might make the impact of any potential interference that much more disruptive to the signal trying to reach your garage.