Thank you so very much!
I was one of the many that made a rookie mistake with the backup and had to do without half my mod these last days; and I can confirm that it is possible and works. And since its downloaded directly via the steam client, I also dont see any legal problems.
So, here's the link to the SteamDB emtry:
https://steamdb.info/app/271590/depots/
Shortcut:
Open the steam console:
steam://nav/console
Enter that:
download_depot 271590 271591 8554066082762790412
Make a backup of the current version, best with RagePlugin. Then just copy and paste everything from \Steam\SteamApps\content\app_271590\depot_271591 (app number may vary) to \Steam\SteamApps\common\Grand Theft Auto V, and you will have version .0 again. That did it for me at least.
Thanks again to ShaeBakes.