If I remember correctly the rockslide purge was the hardest one out there so
A challenge indeed but yeah just make sure to have outer layers to spend time Incase of complete defeat to save as much as you can
The first time I got hit by a Rockslide I sustained significant damage, the first few waves were easy and lulled me into a false sense of security. By the end of the purge half of the base I had been building was gone along with improved workstations, T4 Thralls, 2 horses and the majority of my fighters and Archers. It was a day of great loss I haven’t made that mistake since and now when a Rockslide is approaching I move fast to equip the Archers with better arrows.