The game frequently goes on sale for under $15, providing a safe, verified 100GB installer.
Even extreme compression methods (7-Zip Ultra + LZMA2 + solid block) can only reduce GTA 5 to about at best. Removing multiplayer files, videos, or lower-quality textures can bring it to ~25 GB — but that’s still 50 times larger than 500MB. gta 5 highly compressed 500mb for pc link