Are radiowaves also electromagnetic fields

Radiowaves are basically a color of light that we can’t see. Technically “light” typically only refers to visible colors, and we call everything else “electromagnetic radiation”. Radio waves, microwaves, and infrared light are past the red end of the rainbow, while ultraviolet, x-rays, and gamma rays are past the violet end of the rainbow. All of these are self-propagating ripples in electromagnetic fields.

whether we actually consume or use the electrons themselves or simply reap the biproducts of some kind of manipulation that we do with them

It’s very difficult to actually destroy an electron. When I said the electrons are “depleted” in a transistor I meant they are pushed somewhere else. Electrons can be pushed and pulled by electromagnetic fields, so in a transistor one current makes a field that pushes electrons out of the region where they would need to be for the other current to use them.

In all cases it’s the electromagnetic fields that actually do the work.

If you want to know about electrons actually being destroyed, an electron will annihilate with a positron (antimatter electron) releasing some gamma rays. There are some medical applications for radioactive material that produces positrons which annihilate to produce gamma rays in this way, and then they can detect the gamma rays.