[Arknights] DV-EX-2 Medal + CM - Low-End Squad (w/ Eyjafjalla) 

Take Eyja as a Support Unit (if you don't have her).
You can take extra defenders to block or casters for dps.
Squad used :
Myrtle, E2 Lv.15, S1M3, P6 (doesn't need the Mastery 3)
Beagle, E1 Lv.35, Skill Rank 4, P6
Spot, E1 Lv.35, Skill Rank 6, P6
Hibiscus, E1 Lv.35, Skill Rank 7, P6
Midnight, E1 Lv.35, Skill Rank 7, P6
Kroos, E1 Lv.55, Skill Rank 7, P6
(Support Unit) Eyjafjalla, E2 Lv.90, S3M3, P2 (doesn't need Pot 2)