What you get from Ecclesiastes depends on which view you take. If you imagine Ecclesiastes standing in the pouring rain shaking an angry fist toward heaven, you get one understanding. You get a different understanding if you see her with arms outstretched and palms open in the ancient stance of prayer. A case can be made to support either view. Let me say that again because it is critical.
Some people read Ecclesiastes positively.
Others read it negatively. One person concludes that Ecclesiastes plays the music of life as though it is a funeral dirge. Another person insists that Qoheleth imagines the music of life to be like the Hallelujah Chorus. When you chase the issue into a corner, you will get from Ecclesiastes what you decide you are going to get. The book will mean what you decide it means.