To effectively adapt to an opponent who employs a lot of spin and variation in their serves, focus on enhancing your anticipation and footwork to read their serving patterns. Position yourself slightly farther back in the service box to give yourself more time to react to the spin, while also maintaining a balanced stance ready to adjust to different ball trajectories. Utilize a relaxed grip on your racket to absorb the spin, which will allow for better control when returning serves. Stay alert for clues in their toss and body language to predict the type of serve they might use, and practice your return techniques, such as using topspin shots to neutralize their spin or slicing your returns to disrupt their rhythm. Lastly, varying your own serve returns can help keep them guessing and minimize their ability to capitalize on their spin variation.