I am in the same situation. I have tried the procedure from topham.
All AT commands seem to work and I receive a confirmation RX.
However I have only received data on 2 occasions after many tens of tries.
I don’t know why it worked on those 2 attempts and never others.
When it did work, I was able to send a string every 2 or 3 seconds with no problems but when I repowered either end I could not get it to start working again.
I understand that the Mode setting is lost at power down so I reconfigure both ends at power up