Unfortunately, there is no way to retrieve deleted save data (or fix a corrupted save file) if you have not created a backup copy manually.
Please note that we have no direct access to players' profiles and are unable to enter your game and change its values or progress, add or remove items or achievements etc.
We don't have such power and tools, while no progress or character data is stored at our end.
When it comes to the PC platform - here is where the files are located by default:
- STEAM: *C:\Program Files (x86)\Steam\userdata\**\534380\remote\out
- EPIC GAMES: %userprofile%\Documents\dying light 2\out\storage\
* C:\Program Files (x86) is Steam's default location, but you may find the Steam file elsewhere, depending on your choice during Steam's installation process
** the numbers here will differ for each profile/user
See also: How do I know if Steam Cloud sync works?