How to Set Up Point-to-Point Communication Between Two LoRa-E5 Mini Modules?

When I run your sketch of POST4, it will appear on the serial monitor as follows.

15:00:52.099 → After radio Set RFSwitchTable
15:00:52.132 → State: 0
15:00:52.132 → radio.begin() success!
15:00:52.132 → Transmitting packet …
15:00:52.198 → 2FEE35052DF451589BFB00
15:00:52.198 → Slave UID: 535EE2F
15:00:52.198 → Time: 2 sec
15:00:52.198 → Vbatt: 64411 mV
15:00:52.198 → randomNumber: 5851F42D
15:00:52.198 → VerifyResult: 0