If you look up gta vi free download, the verified details show the game is a paid release

https://wiki-square.win/index.php/GTA_VI_for_free_czy_tylko_wishlista%3F_Najwa%C5%BCniejsze_fakty

If you look up gta vi free download, the verified details show the game is a paid release, while only promotional assets like wallpapers and trailers are available for free.