Also depict the immediately adjacent situation outside the property! (I have not understood the problem so far. A width of 4 m is more than the garage itself offers, so absolutely sufficient as an access road.
Our driveway to the property is also only 4.50m wide. We are then planning a turning area on the property so that my wife can comfortably get in and out of the garage.
I also think that a width of 4 m is absolutely sufficient.
Where it could get tight, depending on the vehicle model, is when the doors on both sides are fully opened – especially with coupes with longer doors – you can quickly reach your limits...