I was curious if they optimized the download. Did it download the 'optimized' ~150 GB and wasting a lot of time there or did it download the ~20 GB unique data and duplicated as part of the installation.
I still don't know but found instead an interesting reddit post were users found and analyzed this "waste of space" three month ago.
[0] https://partner.steamgames.com/doc/sdk/uploading#AppStructur...