According to the datasheet for those modules, the over-the-air-rate can be configured up to 19.2k. However, given the overhead of radio packets, automatic resends, channel coding and the fact it's a LoRa (spread spectrum) means the actual channel through-put will be much lower. The datasheet doesn't provide a best-case throughput, so you will have to measure this yourself. I would have thought that 2.4k is probably the max.