Several things that can help:
- Bring Golisopod if you have it. It disrupts with a ton of them.
- Mega Diancie can mass clear all barriers when you need it.
- Use Barrier Shot SL5 to burst your way through the stage. Super effective options at your disposal are Toxapex, Litten [And more options for people who can afford to: Cryogonal, Swellow, Volcarona].
- The initial board starts off with a bunch of Kartana. Using super effective Shot Out SL5 options such as Noivern and Salazzle [And more expensive options: Rapidash, Spewpa, Vanilluxe]
- Alolan Ninetales can Freeze Kartana for 7 turns, but it is very hard to get off with the board Kartana gives you. Freeze+ can only be triggered on match of 4 and 5.
- Last Ditch Effort and Final Effort give you huge burst at the last 4 / 1 turn, respectively. Heatran and Infernape are good options for this.
Without items, it's difficult if you don't have your skills up to level 5.