Use defensive skills to offset her high-damage skills when you cannot win the clash. If you're still stuck, let me know: Which identities (characters/IDs) are you currently using? Are you losing to the high damage or the bloom effect ? I can give you a more customized team setup!
If a Sinner is trapped, focus on winning clashes to free them.
Dongbaek applies "Blooming" to sinners (stacks up to 5 times).
On Turn 8, she uses a massive Area of Effect (AoE) attack that can wipe the team, which scales based on how many trees are left. Strategies for Success
Here is a detailed breakdown of the 4-48 fight based on community insights: