Did you test the LCD by itself using example code form the LiquidCrystal library examples?
Have you tried the contrast adjustment?
For an I2C LCD display to work, the I2C address and the I2C backpack to LCD pin mapping must be correct. If the library default settings for either or both are not correct the LCD will not work. You can try to figure out the right pin mapping and use an I2C scanner to find the address, but if you install and use the hd44780 library that is done automatically by the library.
I tried your transmit and receive code on the setup from your "RF communication problem betwwen ultrsonic and servo motor" post with the receiver connected to pin 11 and an I2C LCD connected. When I run the code I get "S1: S2: " displayed on the top row of the LCD.
If I set S1 = 1 in the transmit code I get the "S1: S2: " in the top row and "Empty" in the bottom row.
So the radios, code and LCD all seem to be working for me.