STM32 and NRF send & receive
You did not say which library you are using, but based on the #includes, I am assuming http://maniacbug.github.io/RF24

This line in your receiver code:

  while (!radio.available(true));


does not make sense. You are passing true to the radio.available() function, but the function does not care about a parameter.

You probably mean something like:

while (!radio.available());


When you pass in a variable, you are calling a variant of the function that expects a pipe number to be given, and true is defined as 1. Your transmitter, however, is not sending on pipe number 1.