According to cybersecurity reports from Kaspersky and Norton, over 45% of "cracked game executable" files contain malicious code. When you download playgtav.exe from a random site, you are likely getting:

Since the file is part of the game's installation, you obtain it legitimately by downloading and installing GTA V from official sources. The only legitimate way to get the file is through:

PlayGTAV.exe is the primary executable for launching Grand Theft Auto V on Windows. A legitimate version of this file is typically located in the game's installation directory, such as C:\Program Files\Rockstar Games\Grand Theft Auto V . It is a small file, usually around 204 KB in size. If your game is properly installed, you should never need to search for or download this file separately.

This file is never meant to be downloaded as a standalone file. It is automatically installed when you download the game via the Rockstar Games Launcher, Steam, or the Epic Games Store.