Power consumption of 5G is about 20x lower than 3G and getting lower as we speak (there are many 5G technologies only gradually getting adopted). So probably he meant the planned obsolescence mentioned already above.

Any time we increase efficiency, we also increase consumption. 5G increases efficiency, it's true. Now people consume more. It's enables new usages which people will jump on.

This happens in History every time we improve efficiency. Cars now consume a fraction of what early cars did, yet we use these efficiency gains to stuff them with gadgets, and make them bigger, and overall they still consume more than they used now in absolute terms.

In other words the engine inside your modern car is more fuel efficient than the first Ford, but we now make SUV that consume way more to produce and operate, can't be repaired/services easily, and people own multiple of them per household.

This "rebound effect" can be seen everywhere