Did you post to the Mobiflight community?
I was using SimVim which is similar to Mobiflight. Pretty easy to use, etc. but if their software doesn't support something, you're stuck. Also, your entire flight sim is dependant on them being around. If they go belly up, it's good bye also to your project.
For those reasons, I stopped using SimVim and wrote my own code using Python and a Raspberry Pi 4 box. Of course you can still use your Mega and then write your own c code.