Rockstar Games does not distribute the launcher file in isolation. The launcher is installed as part of the game installation process through authorized platforms. The correct way to obtain the GTA V Launcher is to install the game properly through one of the legitimate distribution channels:
Right-click the new desktop shortcut, select "Properties," go to the "Compatibility" tab, and check "Run this program as an administrator." gta v launcher exe file download link
Once GTAVLauncher.exe completes its checks and updates, it executes GTA5.exe—the actual game engine. This is the large executable that does the computational heavy lifting of rendering Los Santos, processing physics, and running gameplay logic. Rockstar Games does not distribute the launcher file