As a general rule the risk of fire in an EV is equivalent to or less than the risk for a conventional petrol or diesel car because of the safety measures that manufacturers have taken. EV fires have attracted more attention because they can be more difficult to extinguish due to thermal runaway, so an EV that catches fire more often results in the entire car being burned out.

We would always recommend you follow the manufacturer's guidance for driving, storing and charging an electric vehicle, so unless it specifically indicates that it should not be stored in a garage there should be no additional risk in doing so.