I used a similar scheme (two computers, one with HID control over the other, and a webcam to observe) as a way to hide a simple aimbot as a proof-of-concept for getting around on-computer anti-cheats that would search through memory on popular FPSs. This was years ago on games with weak anti-cheats, anyway.
It worked OKish. It had to rely on computer vision to do the aiming, so it was significantly slower than examples that would rely on memory pointers or straight pixel recognition from the screen itself -- but the point was proven, the computer that was cheating looked fine as far as memory was concerned.
modern anti-cheats that look at things like pointer movement and player randomness would definitely flag it now-a-days, but I had fun.
The hardest problems were room lighting, which at the time the cheapy webcams had terrible issues with anyway, FPS, and resolution.
Major shortcuts had to be taken back then due to the resolution and fps mismatches between the input and output, shortcuts by which reduced the bot performance significantly, but I bet that'd be a lot easier to deal with today.
Now, my point : I know that a majority of the memory structs are available, documented, and deconstructed for GTA V, having written cheats for the game in the past. Maybe you can exploit that to emulate some of the functions of an IMU?
Lots of vehicle physics variables are fairly easily exposed. "GTA V Memory Structs" google search will get you started on that road, should you care to.
Neat project. Good luck.