The HC12 does have a built in latency, the interface waits a set period when there is no characters ariving on the serial interface, before transmiting the actual packet.
Typical SPI connected radio devices send the data as soon as the outgoing data buffer is filled.
You might get a NRF24 setup to work at that distance, but the SX1280 2.4Ghz LoRa device seems a good choice, it should cover that distance and has lower latency, higher speed and no legal duty cycle limits versus the UHF LoRa devices.
See here;