Again I ‘must’ update the MSFS2020 but that update stops (again) at 80%. I remove MSFS2020 from my hardrive to give a fresh install a chance. Starting the installation from the store (or XBOX) it downloads some1,7 GB only but the file size should be 127 GB.
But once you have done the initial download via the MS Store the installation should continue when you launch MSFS, i.e. allow you choose an installation location and download the game packages?
Unless of course I am misunderstanding you! 