I also left the beta and had this exact same issue. The MSFS Icon was gone from my start menu but the game was not actually deleted. I went into the store and logged out and then logged back in. I then went to Xbox app and under Installed it showed MSFS with an error. I clicked that which took me to another screen were I hit resume and then it immediately showed that the sim was installed and the error was gone. I was then able to find the MSFS Shortcut in my start menu again and launch the sim. After launching the sim it tried to make me update all the content in the default C: directory but since I have all of that installed on a separate drive I pointed that folder to my already installed content and then the sim launched just fine. So, you should not have to re-install from scratch…