It is some .ini file. Search all ini files for that folder name. Then just edit it or change.
Also you can ask some “pretending to be intelligent” things like ChatGPT for list of possible places where that ini may be.
Or use tool like TotalCommander to search folders for ini file that contain “fortnite”
“pretending intelligence” gave me this:
%ProgramData%\Epic\EpicGamesLauncher\Data\LauncherInstalled.dat
its json that keeps info about what is installed where
apparently you can also make Symbolic Link to new folder from command prom as administrator:
mklink /D “C:\Program Files\Epic Games” “D:\Epic Games”