If it’s a steel frame then it will easily tolerate 5mm of flex either inwards or outwards at the dropouts. I have a steel frame with 130mm spacing and 135mm wheel and have ridden it without problems. My suggestion is to remove enough of the washers to give you enough axle protrusion so the nuts get enough purchase to keep the wheel from slipping.
If it’s a steel frame then it will easily tolerate 5mm of flex either inwards or outwards at the dropouts. I have a steel frame with 130mm spacing and 135mm wheel and have ridden it without problems. My suggestion is to remove enough of the washers to give you enough axle protrusion so the nuts get enough purchase to keep the wheel from slipping.