Q.what’s causing brown spots on fig leaves
This is a tree/bush that was cut back to ground. I have tended to it and got it up approximately 3 ft. high. Brown spots come on leaves, not all of them, and no fruit is setting yet. Then it dies back in winter.

There are a number of diseases that affect figs, which would be consistent with the symptom of spotting on the leaves. This discussion could give you some insights: https://www.gardeningknowhow.com/edible/fruits/figs/common-fig-tree-diseases.htm
A good maintenance plan will go far in protecting any plant from disease and pests. Here's more information on growing figs: https://www.gardeningknowhow.com/edible/fruits/figs/how-to-grow-figs.htm
For an identification of the particular problem, and advice for treatment, go to the county extension service. This article will help you locate one: https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm