Steam allows you to select which DLC you install. For GTA V, you can uncheck the "Ultra HD Texture Pack" (saves 15GB) and uncheck "GTA Online" (saves 30GB). By installing only the Story Mode, you can get the game down to roughly without any compression artifacts.
: If a modern AAA game is less than 50% of its official size, be extremely cautious. gta 5 highly compressed 20gb new
Have you encountered a suspicious “highly compressed” game download? Report the site to your antivirus provider and avoid clicking any “download” buttons. Steam allows you to select which DLC you install