I had already developed a solution for BLE communicating between Apollo3 and Linux ( Raspberry Pi/ Ubuntu). I have now extended this for BLE between 2 Apollo3 boards, one running as client other as server. https://github.com/paulvha/apollo3.
Based on the Ambiq Amdtp client menu structure : It can exchange test data, set the server led on /off, perform a simple chat, set and read any digital pin, read any analog pin, read the internal temperature , provide the battery level in percentage and (if enabled on the server) provide BME280 data to the client
It will work on both with the current 1.0.30 Apollo3 board library, as well as the adjusted library containing the more secure EXACTLE/Cordio from Ambiq 2.3.2 using the normal Arduino interface structure.