Can I play Grand Theft Auto V offline on Xbox One S?
The "you need the be online" thing was very confusing at the beginning. I'm using and Xbox One X and Xbox 360 and I can play GTA V offline on both of them.
You don't have to connect to the Internet when you buy the game. I believe the game license itself downloads with the game.
But if you're planning to play through Xbox Game Pass or if you bought the game free from "Xbox Live Gold Games", the console might need to check if you're still subscribed to Game Pass or Xbox Live.