First: try to join a vanilla server (select vanilla in the search options). Maybe there is a problem with the steam workshop.
If it didn’t work, could you check the task manager while the game is stuck at the queue position #1 screen? If either Unturned or Steam is using the disk (the value in the disk column isn’t 0), then just wait. It can be still a bug, but give it a chance.
Finally a random thing I found on the internet, idk if it’s true: special characters in your name can cause this, try changing it in the Characters menu (ingame). Or even check your steam name.
I hope this helped.