The goal of doing good is not to triumph over evil. Evil will create its own ends, that is the nature of finite games - games that are played to win or lose. No, the goal of the good life is to find the path that leads you to the other game, the infinite game.
In the infinite game, the goal is a relentless pursuit of peace and fairness, to continue ‘pushing the wheel of justice forward,’ as famed explorer Wade Davis terms it. This game goes beyond binaries, it's hard to know what is right or wrong. Instead it involves doing whatever ‘robustly good actions’ you can today that otherwise prepare you to act when the time comes. And when the end point is this type of lifelong pursuit:
“you then never expect to win. And if you never expect to win, you’re not disappointed when you lose. And because of that, you can keep fighting with the same idealism, the same energy when you’re 69 years old…as when [you] were 20 years old.” - Wade Davis
Free from the burden of winning or losing, energy and idealism are easier to come by, even in the face of setbacks. Meanwhile, we can find solace in the knowledge that evil is working on its own demise:
“Evil always contains the seeds of its own destruction. It is ultimately negative, and therefore encompasses its downfall even at its moments of apparent triumph. No matter how grandiose, how well-planned, how apparently foolproof of an evil plan, the inherent sinfulness will by definition rebound upon its instigators...It will founder upon the rocks of iniquity and sink headfirst to vanish without trace into the seas of oblivion.” - Good Omens, by Neil Gaiman and Terry Pratchett