Are you setting FS_XTALT correctly? When using the chip directly you need to measure and set the crystal tuning yourself, if this isn’t set then the frequency can be off and you’ll have trouble communicating.
For the modules you also need to set this but assuming the driver is correctly written it will be automatically reading the factory set value from the OTP and applying it automatically on startup.
Set one of the modules into RF test mode and find the spike on a spectrum analyser (you’ll need one that goes up to the centre frequency of the channel in use). Then put your board into RF test mode and adjust the crystal trim value until the two spikes are on top of each other. Save the correct value of tune into the OTP for that board.
Repeat for each board.
If you don’t have the equipment to do this then try a default guess of a value of 0x0F (middle of the range) and see if that works (don’t program this into the OTP). It doesn’t have to be perfect to get communications but the closer you are to the correct value the more reliable and longer range the link.