This is happening because of only 2 different reasons.
First, you never installed .net Runtime 8.0. It is installed with the installer we provide but if you cancelled it then that would be the cause. The link is below. Install the Desktop Runtime.
The other reason is more then likely you have installed 2 different versions of MSFS. The application will not run because it is looking for MSFS. Check the following link and make sure only one exists.