I think I just noticed a plot hole in Rebels, why would the dead witches want living bodies if they can’t even leave the cave?

I’m watching ToTE Ep1 when all the witches are supposed to be wiped out by the attack we see from a different pov in TCW. I can understand the souls/ghosts/what ever you want to call them wanting to possess new bodies to rekindle their magik but if they can’t leave the cave and the grandmother lady that was able to bring all the dead back to life is dead herself it seems really short sighted. Wouldn’t it be better to be a disembodied figure that doesn’t food or water or sunlight if you have to be in a cave that you can never leave?