When looking at multi-viscosity oils ie: 5W-30, the first number, 5W is the winter weight of the oil. This is the viscosity of the oil when the engine is cold so that the engine is provided with lubrication is soon as possible when it’s started. Once the engine reaches operating temperature the oil has the viscosity of a 30 weight oil.
So you can use a 0W-40 oil if you want. It just means the oil will flow faster on a cold start than a 10W-40 oil. But both will have the viscosty of a 40 weight oil once the engine reaches operating temperature.
Tester