What boards are you testing with?
The datasheet is for the SX1231 transceiver, not for the RFM69 module. The hoperf just slapped their logo and replaced photos and called it their work in typical shameless chinese style.
But if you want to build your own board then you can probably do it better than you see on the RFM69 modules. Even though, these modules have been used in so many places, even high end and extreme stuff, and they work well, that I don't think your efforts are worthwhile unless you like the hobby and have the time and slightly better margins give you the satisfaction.
Otherwise ... use what works, don't fix what's not really broken, and move on. Life is too short.