Question plastic, rubber and low humidity

Is it possible to maintain an environment with low humidity to preserve electronic devices from oxidation without this low humidity drying out plastic and rubber from electronic devices and DVD discs that are plastic and in that environment? in my room I have two digital hygrometers and an air dehumidifier plus 300 with q compressor that stays on all day because the humidity goes up to 70%, while in the dehumidifier the humidity is at 40% in the hygrometers the measurement is at 50% so I set the dehumidifier to 40