Of course this is the part where I need more work. It's far from finished. At the moment basic functionality works:

• Both SX1280 modules are used. In transmit mode I alternate them while in receive mode they are both listening.
• Acquisition works: the receiver jumps to a random channel and scans through the channels 3 times slower than the transmitter. Eventually, the transmitter catches up with the receiver. In tracking the receiver adjusts its heartbeat timer to the received packets, to make sure that the transmitter and receiver will not drift out of sync.
• From the transmitter point of view every 4th packet is a downlink or with other words the receiver sends a telemetry packet.
• Communication with both the BMP388 and BNO055 works. I added a little C++ wrapper around the library that Bosch provided

In my github repo you can find all the pieces, but the whole firmware is not put together. When I'm working on one part I usually comment out some code. Eventually they all will be glued together...