It would work as advertised if you were using FSX or P3D. It comes up short with MSFS. The author of that app did absolutely nothing to make it work with MSFS. It just so happens that MSFS also uses SimConnect, so some of it worked. And that was good enough for him to declare it MSFS compatible.
But like I said, he didn’t claim that in the Google Store description. False claims would get his product pulled with enough complaints. And I’m sure the 10 min preview time you get before you have to buy it is also well planned to get people to see the basic functions work, then buy it to be let down that more important ones don’t.
If you’re looking for external apps to control your cockpit, you might want to check out this thread. It will require a touch screen (you can use your tablet + SpaceDesk) to fully control the in game G1000.