I’ve never used iNav so I have no idea whether the iNav telemetry Lua script would be likely to work with ArduCopter. Since it looks like you have everything wired and configured the same as me, and mine is working, I’d suggest the next step would be to install yaapu on your Taranis and see if that works. The thread here is pretty long now, and full of useful information. You could scan that and see if someone else has had a similar issue to yours.