Seems like you have a narrow view of what Positive Psychology is focusing on. While you're right that many authors focus on "happiness" as commonly understood, the concept of Eudaimonia (a life well lived) is also a focus for some researchers.

A great read for you may be The Good Life: Unifying the Philosophy and Psychology of Well-Being by Michael Bishop.

https://www.amazon.com/gp/product/B00YD26TIS/