in the bathroom, I have a double switch. The first activates the main light and the fan, that is, the light in the bathroom and the fan turn on at the same time, and the second activates the mirror with the LED light. The main light in the bathroom is already smart, in the sense that it is a smart wifi ceiling light, which I can control from the smart life application. The problem is that the fan is not smart, and every time I turn on the light in the bathroom, the fan automatically turns on. What I would like to automate, would be with the help of a sonoff relay connected to the fan, and a humidity sensor, to create a scenario so that the fan starts only at a certain humidity set by me, not every time when I turn on the light in the bathroom. Or would it be an option to get a smart switch?

In the case of the situation where I would use the sonoff relay and the humidity sensor, it would mean that the switch that activates the light and the fan should always be on, the fan should start only depending on the humidity, but the light would always have to be turned on/off from the application on the phone? if someone else wants to turn it on, how do they do it?

I am open to any other solution/variant. I’m still at the beginning with the smart home part and not everything is clear to me yet