How much energy from the Sun could we get if we use Jupiter as a gravitational or atmospheric lens?

A lens deflects light rays, bringing them to a focus. A gravitational lens is typically a galaxy or cluster of galaxies. A galaxy typically has trillions of stars.

The sun deflects light rays a little. See How the Sun Warps Starlight, or Gravitational deflection of light. A ray that skims its surface is deflected by about 1.8 arcsec. These rays would come to a focus 542 AUs away. This is far outside the solar system, about 15 times farther away than Pluto.

The deflection by Jupiter would be far less. The Sun has 1000 times the mass of Jupiter, and the surface gravity is 11 times stronger.

The deflection of starlight by Jupiter is predicted to be 0.00119 arcsec and measured to be just about exactly that. This deflection is about 1500 times smaller than the Sun's. The focal length is 13 light years.

Of course, this is just the rays that skim the surface of Jupiter. Rays that pass it farther away are less deflected, and meet even farther away.

So this isn't a good way to get more energy from the Sun. To use it, you would have to go to the focus, 13 light years away. At that distance, the Sun would be just a dim star. It would be slightly less dim if you were exactly at the focus than if you were nearby. You get a lot more energy from being on Earth, which is much closer to the Sun.