BE SURE TO MAKE A BACKUP OF YOUR GAME FILES BEFORE ATTEMPTING THIS
Step 1: Download DepotDownloader: https://github.com/SteamRE/DepotDownloader/releases/tag/DepotDownloader_2.3.6
Step 2: Extract DepotDownloader
Step 3: Go into the Folder that you extracted DepotDownloader and click the address bar.
Step 4: Type "cmd.exe" into the address bar and press enter.
A Command Prompt window should have opened and it should show the folder that DepotDownloader was extracted to in the window.
Step 5 : Find the version you want to download from SteamDB (you need the manifest ID): https://steamdb.info/depot/1097201/manifests/
Step 6: Plug the manifest ID, your steam username and password into this command line: dotnet DepotDownloader.dll -app 1097200 -depot 1097201 -manifest <ManifestID> -username <YourSteamUsername> -password <YourSteamPassword>
Step 7: Copy and paste the command into the command prompt window and press enter. (If you have steam guard enabled you'll have to enter the code)
Step 8: Wait for the download. It might look like it's frozen, but just be patient.
Step 9: Press Win+R to open a run window.
Step 10: Paste this into the run command and press enter: steam://open/console
Step 11: You should see the console tab open in steam. Go into that tab and copy and paste @AllowSkipGameUpdate 0 and press enter then paste @AllowSkipGameUpdate 1 and press enter.
This command keeps steam from updating games until you reset your client.
Step 12: Go to where the game is installed (Right click the game in your library, press properties, browse local files)
Step 13: Delete all the files in the folder.
Step 14: Copy all the files from the depots/1097201 and paste them into the steam folder that you deleted the game files from.
You should now be able to play the downpatched version of the game.