You are of course entitled to your opinion, but I spotted a logical inconsistency: You say you “wish that there were a good God …. who would also undo the cruelty of the food-chain, where animals are required to eat each other if they have any desire to live and to feed their newborns.”
If you believe in God, then you know that animals have no souls, and their deaths are justified by their use as food. If God didn’t want us to eat animals, he wouldn’t have made them out of meat!
If you don’t believe in God, then there is no cruelty, just the workings of nature: The survival of the fittest is what drives evolution. You can’t have it both ways.
I have two other thoughts to share with you: God doesn’t see this life the way you do: all mortals must die, and it doesn’t matter much whether you die young or old: the difference between 3 years and 90 years of life is inconsequential compared to eternity. All this stuff about the thousands who drowned in the Flood has to be viewed from God’s point of view, as putting them out of their misery as they were destined to not go to Heaven anyway. To God death isn’t a problem: the state of your soul is.
The other thought is that Jesus wanted to change people’s behaviour, to make them treat other people with kindness, rather than with anger, hatred or callous indifference. To convince people, he used the reward of Heaven vs the punishment of Hell: its the old carrot and stick principle. If it leads to people treating each other better, the threat is just as justified as the promise of reward.
Whether you believe in God or not, the ethics of “Love thy neighbour”, and “Treat others as you would have them treat you” underpin almost all Liberal thinking in our modern western culture.