Aside from the notion that suffering is more powerful that "any positive experiences" -- a vast and very subjective generalization -- suffering itself is not established as 1) having objective value beyond context, or 2) serving as a primary means to measure life's value in the first place. The first objection means that suffering is relative, e.g., "the first-world problems meme." The second objection calls into question the idea of suffering as a measure of value.
If you assume that there are more negativity than positivity, then life becomes depressing. If you become mindful, and appreciate the small things in life, you'll soon realize that life is full of wonders and happiness. It's all about the mindset. Psychedelics can aid in getting the right mindset.
I'd say love is a pretty powerful feeling too. We have to learn to love who we are and roll with whatever suffering comes our way, because this life is all we have. Even though there are ups and downs, there is always hope and certainty that something good will come, sometime in the future.
Your opinion is overbearing (überheblich); you take the opinions the view from other away, and say that the wold (ontology) is negative. But the can not there be truth about the value of life. Each one set the value of life for himself, but is not a ontological fact.