Then Solomon was not wise....he was a privileged fool.
Solomon was so wise that he made a fortune offering advice to the leaders of nations around him. We'd call him a consultant these days. Yes, he had some character issues that were not so helpful. Perhaps you should read the book of Proverbs. A great deal of the advice applies to life in general, not just to Judaisim or Christianity.
Without God, a man's life is no more significant than a stone thrown into the ocean. There are a few ripples and that's it. If you don't like Solomon, perhaps Shakespeare is more to your taste?
"Life’s but a walking shadow, a poor player that struts and frets his hour upon the stage and then is heard no more. It is a tale told by an idiot, full of sound and fury, signifying nothing." Solomon is a little more pithy, Shakespeare more eloquent. The sentiment is the same.