Like all Palworld bosses, you should aim for headshots, but staying alive should be your main port of call. Utilize cover, time your shots well, and Saya & Selyne should fall in no time.
Prunelia in Palworld is a new Grass and Dark type Pal you can get in the monster-tamer game. The Pal is one of the many additions that came with the Feybreak update.