Get gud!
But for real, expansions should, in my opinion, try to push the limits of the players, making them master the skills since they are end game content.
If you are having trouble and you don't want to lfg for someone to help you you can always review your build. If you don't like to copy one from the meta just go check one out and figure out what works there and what you would need to implement in yours.
For myself I found that it was too hard for me to stay alive with a berserker set while in those new maps when I was alone, so I switched to soldier and edited my build for a little more survival, with skills that would make me more mobile to get out of a hard situation.
Trust me, this is a new interesting level to the game and once you'll grasp it you will fine that you can do much harder stuff like a pro.