Resistive loading effect voltage drop
To be able to use a voltage divider you need to power a device that draws a constant amount of current.
The drawn current should be very low or else you'll lose power by heating the resistors (actually no matter how low your current is you'll still lose power).
If your module is expensive, use a voltage regulator (it's cheap and safe) or a converter that has a reliable design with no risks of overvoltage.