I had an issue after last 5 days dealing with files stopping to respond during an installation (decompressing).
I have found that last time that I was connected on MSFS, I have changed my server region from standard (Europe) to USA EAST.
Means, my MSFS region it was different of my Steam region.
After I have changed again my standard region to Europe (Automatic) on MSFS I’m now able to install packages of MSFS.
I have done a new installation without any problems again.