The ICE does power all the electronics.

All car engines have a generator ("alternator") attached, which generates the electricity that the car needs. Taking power from that generator puts a drag on the engine's shaft, requiring more fuel to be burnt to keep the car going at the same speed. There is no such thing as free energy, it has to come from somewhere.

There is also a rechargeable battery in the car, used when the engine is off. That battery is recharged from the generator when the engine is running. So any power taken from that battery, requires more power from the ICE to recharge the battery. Again, no free energy.

Air conditioning usually connects the AC compressor directly to the engine shaft (via belts). Again, when it is running that puts a drag on the engine's shaft, requiring more fuel to be burnt to keep the car going at the same speed. (The AC needs a lot of power, so this design avoids the inefficiencies of having the generator drive a big electric motor to drive the compressor. It also avoids the weight and space for a big electric motor).