Offer mud flaps to reduce spray on the rear fenders. They would need to be sized for the lowest suspension setting.
Very cheap at an accessory shop. Should be easily fitted on the front and rear.
Moderator: The author hoped mud flaps would reduce dirt on the rear camera, but most of the dirt occurs due to the low-pressure effect at the rear of the car due to aerodynamics. Mudflaps would have little effect on reducing rear camera dirt.
Mudflaps are available from Tesla for the Model 3 and Y. Third-parties also make mudflaps for Tesla vehicles.