This Sicilian black is quite healthy with lots of fruiting. What is going on with the spotting leaves and the yellowing?
One of the possible causes is fig tree rust. It is typical for this to show up late summer, early fall if conditions are very humid, the plant is being overwatered.
If that is the case some steps you can take is to be sure to water only the media not the foliage. Also be sure to only water as needed, figs come from a dry Mediterranean climate and too much moisture and humidity generally leads to their decline.
If the condition continues check locally for available fungal treatments!
I agree with the above comments. Living in Malta I have a number of ficus carica Bonsaï, also in the wild this seems to be a seasonal reoccurrence. Don’t worry. Eventually the leaves will die back naturally and loose the leaves for the winter. You will see the green nodes for next years growth ready. These may turn a little brown in the winter but will bud back once the weather starts to warm up again. Early spring before any new growth starts is the best time to cut back branches to just above the dormant node you wish to encourage growing. Hope this helps