The BNO085 is difficult to buy these days, so it’s worth having a look at the Arduino Nano RP2040 Connect board with its integrated IMU I think.
A prototype implementation using this one for AgOpenGPS can be found in my Github repo. The IMU itself is as good the the Bosch sensor of the BNO, but there is no magnetic sensor and so a continuous calibration of the heading isn’t possible so far. A certain drift is remaining, but may be eliminated in combination with AgIO one day.
With the Python script, the sensor emulated an BNO085 in RVC mode being compatible with the AgIO mod described in these posts here.
Edit: April, 3rd: No key (no soldering at all) needed any more when used with the enhanced AgIO.exe