blackButtonState = digitalRead(BLACK_BUTTON_PIN);
Does not give any indication of using the wireless module.
The wireless module does not have a black button.
This module requires data to be sent, it is not a press button on Tx and change state on Rx.
You need to set it up as having an MCU read the button on the send end then cause a piece of data to be sent to the other end. When the Rx receives the data, it becomes the black button on or off.
If you simply want a press button to operate a relay closure, you have bought the wrong device. Refer to earlier post with link to that type of device.