I have already addressed the "Meaning of Life™" & recently saw the Dalai Lama's own excellent response to this idea that our lives have some ultimate "purpose."
To avoid over-simplifying the problem, he splits it into an ultimate aspect and a practical aspect.
After he finishes picking his nose while thinking about it...
• "On a deeper level, I DON'T KNOW..."
• "but the immediate purpose of life is EXISTENCE!"
This is simple, penetrating wisdom that is one of the reasons I consider the Dalai Lama a major influence on my own views.
Some may find those answers to be totally obscure, but it is as close as human language can get to the essence of the situation.
Of course, like any religion or sect, there are sides of Buddhism that can be considered 'dark', but these aspects of life can be understood & sublimated like anything else.