I skipped most of this series, i wish i had the patience not to, about eternal life i have decoded in threads like this
Thread: The Biblical Flood Decoded! It Was An Alien/Lunar Genetic Disease/Plague On The Entire Human Race!
we were all immortal in ancient times until some sick individuals invented a genetic disease that gave us 70-100 years life expectancy.

So to see the same ones selling us eternal life is like snake oil selling as they were the ones who robbed us from it in the first place.

In the end they plan for earth/krypton/asgard to explode so reinventing immortality can be their last and farewell joke/prank on us.

Man of steel showed the destruction of krypton/earth is also crucial to the escape of the lunar scum from earth.

Thor ragnarok showed similar thing where one eyed thor had to blow up his own kingdom to escape hela.

By the way the substance in defenders the hand society was talking to give them immortality in daredevil 2 was shown of them to farm it and harvest it from human prisoners in their basements.