No, not everything in life is a raging dumpster fire. But that's not the point. There are (by far) enough negative/unwanted elements of human existence to justify either its dissolution, or a drastic change in how it works (on a fundamental level). Suffering is the only constant in life. In pain, there is suffering. In pleasure, there is suffering. Suffering is the only thing about human existence that can truly be relied upon. Suffering, of course, is what drives humanity forward. It is what fuels progress, on every level. But why do we even need to progress? Is this "driving forward" of humanity even consensual? Did you, or me, or anyone else, agree to take part in this progress? Why is suffering, (a fundamentally unwanted thing), needed for progress? What's it all leading toward? Is it even worth it? Is human existence even necessary? Why would it be necessary? Because there are good things in life? Well yeah, sure, there are good things in life. But there are also bad things, which makes the whole thing (life/existence) not worth it. It's like, if someone offered some cake to you, (let's assume you like cake), and some parts of the cake were delicious stuffing, while other parts were made of dog poop, and in order to enjoy the cake at all, you had to eat the whole cake, any sane/reasonable person would decline the offer. Life/existence is the same as that cake. Not to mention, of course, that the lowest lows, are always much more bad, than the highest highs are good.
"Imagination, life is your creation"