Last winter my figs had no such signs at all. Not even in very shaded branches. I did see scale and those leaf
eating bugs but no fungal spots on any of my fig varieties.
This year a friend gave me a fig that was infected,[lots of lower and inner leaves had the spots]
While I tried confidor, mancozeb and echo oil it just got worse until all the leaves had it and gradually dropped off.
My other figs on the same bench showed signs first so I think it came from the same tree.
That's what made me try the lime sulphur which in my case has been good.
IMO it does the job. The other measures only exacerbated the problem but the lime sulphur spay has stopped it spreading.
It looked like fungal infection to me and the spaying has helped

However I'm still intending to follow Aubigfigs example and defoliate all my figs and bin the leaves
The man who gave me the fig I mentioned has the same problem on all his figs. He tells me he defoliated earlier in
September last year due to the infection that he thought was a water issue. That clearly didn't work too well.
On the plus side it does make the trunks nice and clear looking after spraying
