If someone were to explore this space, they would use a dedicated, non-admin user account, run the installer inside a sandbox (like Windows Sandbox or Sandboxie), and scan the final game folder with multiple antivirus engines. But the only truly safe option is to buy the game.
No one creates a high-quality RePack for a game that isn’t in demand. GTA San Andreas has an unusual, fractured digital history that fuels the RePack ecosystem.