I need to send 4byte messages from Arduino Uno with transmitter STX882
That is not possible. BLE and ASK (STX882) are totally different protocols, and the STX882 uses the wrong frequency band.
Use the BLE library for the Nano33 BLE to send messages. Start by studying the built in examples in the Arduino IDE, and/or tutorials you find on line.
You might find this discussion useful: Communication between TWO Arduino nano 33 ble sense