I had the 949mb download. After that I started the game then it took me back to the store a second time where I had to install MSFS a second time. It was only a small update though, it was not a re-download.
After those two sets of store updates I loaded the game where it installed a 12GB patch.
I rarely have an update issue but the prerequisites and install method really is horrible. Going by the trouble shooting steps there is way too many moving parts that have to be “just right” to work reliably.