So, I have tried a lot of stuff but my App Store keeps getting stuck downloading the OS update that you see in the first picture below.
I have tried canceling, restarting, deleting some files Library/Updates folder, also deleting some files in open $TMPDIR../C
The last thing I tried was doing what is suggested in this question Mac App Store update stuck (Installing - Calculating...)
I am getting desperate because no matter what I do, when I try again, the update hangs at 125mb and the waiting time keeps going up when I wait.
What are my options at this point?