I use tanglefoot bought from garden center.
All natural ingredients.

Like a sticky grease that can be applied to tree over tape or other ways and the ants cannot pass it or the get stuck to it.
Been useing it for many seasons now as the ants will get inside your fig.

There are other methods but this one is just 1 example.
Martin

In addition to the possibility that the ants might eat the sugary part that oozes out of the fig, or even venture inside and try to eat the fig, ants sometimes "farm" scale insects or aphids. These insects excrete "honeydew" that the ants like to eat. And the ants protect these insects from other predators. These scale insects and aphids can sap the strength and energy from your plants.

So while the ants likely won't damage your tree directly, they're not something you want living in your pots.

Perhaps you should check for scale while you're at it just to make sure the ants aren't living near their little feeders.

noss