The safest and most recommended way to obtain the GTA V launcher or any updates to it is through official channels:

A fake GTAVLauncher.exe might work perfectly—except it logs your keystrokes. Hackers will get your Rockstar password, but also your email, bank logins, and Steam account.

Even if a cracked launcher works, you cannot play GTA Online. Rockstar’s servers verify the launcher signature. A modified EXE will result in an instant ban or a "Files required to play GTA Online could not be downloaded" error.