I have done some limited development in the past (for personal use rather than professionally) so I may be able to have a crack at this if I know where to start. (On the other hand, if anyone more experienced wanted to weigh in with the code I'd be happy to test). Original mGBA...
The solutions other emulators like citra does is they support DSU which is a protocol made to pass the sensor data via a server. There is support for this on the deck and it makes the gyro essentially perfect on citra. Endrift however did not wanted to add support to DSU and would rath...