So as many are aware, the 1.08 beta made it so pressing F2 twice does not allow you to move around early when a level is first starting up. However, there is still a way to do this.

You must use the old Vermintide 1 method to do it. When the loading screen for the level is done, and the game fades to black briefly, hold down TAB and right click. It also might help to bring up chat briefly. If you did it right, you should see your cursor pop up on the black screen and once the black screen ends, you should automatically be on the TAB screen. Press Esc to get out of the TAB screen and you're good to go. You can move around early like before.

This is fairly consistent but can be tricky to learn. If you're having trouble, perhaps look up a video or another post on the subreddit explaining it better than I can.