Rockstar Games now allows PC players to pre-load the GTA 5 Enhanced version and migrate the story mode save game from the Legacy (old) version.

Rockstar Games is officially bringing Grand Theft Auto 5’s next-gen upgrades, which were previously released only on PlayStation 5 and Xbox Series X|S, to PC platforms at long last. These new features ...

In case nothing works, you can try reinstalling the Rockstar Games Launcher and Social Club applications. To fix the GTA V verification error, you can verify the game files on Rockstar Games Launcher.