How does something afterwards change the meaning of this in a good way?

Why fight for justice? E.g. the bible says god will judge and that i shouldn't. So if I just don't care about anything here but about god, I might have a bad time now but eternal happiness later. How meaningless is now this here? Everything is transactional. The love that you gave is for the sake of getting some much much more valuable later.

Why do people find happiness even in the worst situations? Because it is the only way to deal with it. We are made for survival and survival requires the willingness to survive. It doesn't matter if you are the strongest fighter, if you don't even want to fight back. Your desires come from survival needs.

And a little extra bit, there might not be a point in living. It might be meaning less. But I personally want to be happy. I just do. So everyday I work towards being happy. As I personally love my family and friends, I wish them to be happy. I just do. As my friends have family and friends, and their happiness is somewhat linked to their family and friends happiness, I want all of them to be happy too. And so on. As I can relate to the joy of being proud of oneself, I want them to feel that joy. And so on. None of this is objectively meaningful, I just like it that way. And I might be an asshole but I don't care if you agree with me, I want you feeling happy and fulfilled. Deal with it.