Battlefield 2042 will have three main game modes. The first is called All-Out Warfare, which is a fancier name for the older Conquest and Breakthrough, but on a much larger scale. Hazard Zone is the second, which is likely where the environmental hazards come into play. EA has not revealed what exactly the third one is, opting to only reveal it on 22 July.
As for the game’s release, Battlefield 2042 will be out on 22 October 2021. Pre-orders are already open, and those who do so will get access to an open beta. Buy any of the non-standard editions, and you’ll be able to play the game a week early, on 15 October instead.