https://www.gamespot.com/articles/battlefield-5s-grand-operations-wont-be-available-/1100-6460798/

One of the big new features coming in Battlefield V is Grand Operations, an "upgraded version" of the Operations multiplayer mode introduced in Battlefield 1. However, it appears players won't be able to participate in this new multiplayer experience until after the game releases.

EA shared more details about Grand Operations in a new post on the official Battlefield V website. Most notably, the post reveals that the first Grand Operation will be available "shortly after launch." No other timing details were shared in the post, so it remains to be seen how long players will have to wait to play the first one.