Warning:

This save must be installed on top of your save! If you do not want to lose your progress in the game, then make a backup of your save onto a regular flash drive (which your console reads) and leave a copy of your save on your computer/other flash drive. This save occupies the first save slot in the game!
The game may take a few minutes to load this save!
Performance on PS5 - NO.

If saving on your console does not work:

In order for this save to work for you, you need to run the save file through the "Save Wizard for PS4 MAX" program. This program “overwrites” the save from my account to yours.
Peculiarities:

Completed the game;
All weapons are fully upgraded to 100%;
You can start "New Game+".
Installation instructions:

Unpack the archive and from there transfer the “PS4” folder to a flash drive that the console can read.
We insert the flash drive into the console and transfer the save data to the console.
Transfer instructions:

Insert the flash drive into the console => “Settings” => “Manage saved application data” => “Saved data in a USB drive” => “Copy to system memory” => Select the game => Check the box => “Copy”.
Instructions for working with "Save Wizard for PS4 MAX" (thanks for the help Mrsergo222221):

Insert the flash drive into the computer => Go to Save Wizard for PS4 MAX => Go to the tab
"re-sing" => Click on the "import" button => Select the archive to save => Click on save, and then on the "import" button => Select your PSN profile.

Author: OSKaR2255