You can find more information about her on Tibia Wiki. I don't know if it would be possible under level 100 but the strategy is the same. https://tibia.fandom.com/wiki/Zushuka
She will start off the fight invincible. You'll have to take the pick from the altar in the center and run to the west and east to destroy all of the ice cubes. When the pick disappears you will have to run to the center to get another. It only lasts 5 seconds. As you are running Frost Spiders will be spawning that will get in your way and paralyze you. You can use energy bombs to keep the path clear so you can make it to the ice cubes with the pick. You may also want to lure Zushuka away until you finish with the ice cubes.
Once the ice cubes are destroyed the invincible Zushuka will despawn and a new one will spawn at the altar with a darker outfit. At this point you should be able to just SD her. When she gets low she will recover half her health. This will only happen once then she can be killed normally.