EM cat can launch aircraft beyond 40t.
EMALS's launch energy is 122MJ. PLAN papers often quote this number in their design too, so I assume Fujian's figure is around the same. To compare, steam cat's launch energy is 95MJ. So EM cat is 28% higher meaning 1.28 times of max launch weight. If F-35A's MTOW is 32t launched from a steam cat, EM cat can in theory lauch anything up to 41t only limited by structural strength of the aircraft.
Another thing to think is that steam cat has huge force at the begining and much lower force in the end. This means given the equal launch engergy (accelerating the same mass from 0 to takeoff speed), aircraft will be subjected to mucher higher stress from a steam cat. This means even if the steam cat's top energy is enough to launch X tonne, it may break it, so EM cat can always launch heavier load with the same energy.
Note that the F-14 MTOW is even higher than for the F-35