Hi Andrew, two comments.

One is a heads up, you seem to have had a strong reaction to Williams' book. You may be suffering from what I call "first book syndrome", which is when you read a book that upends your previously unquestioned worldview and leaves you feeling as if the universe has spoken to you and told you it's secrets. If you are, and you're lucky, you'll have similar reactions a few times and eventually realize that all of those works are important because each contains a kernel of "truth", and that none is the whole story.

The second, and I've seen this a fair amount, is what I think is a misunderstanding of suffering. It isn't about ‘sure that was hard, but God put you through it to take you to better places.’ It's about the reality of everyone's lives prior to the inventions of pain killers, surgery, dentistry, and effective medical treatments. The only way to deal with pain was to endure it. If you had a debilitating injury that modern medicine can heal, too bad, you'll be suffering from it, and having to endure it, for the rest of your life. Wealth might insulate you from the sufferings of poverty, but it couldn't buy you health. That was the equalizer, in the end everyone suffered. Unlike today.

Which I think is why is why every major religion preaches enduring suffering, because until pretty recently there was no avoiding it.