How can a caster deal with an enemy using antimagic field?

I'm playing as a high level wizard and I faced an enemy with this spell.

With some roleplay after the fight (in which I didn't do anything), we discovered that there is a big chance that the BBEG has this spell too.

The feeling of playing and not being able to do anything is horrible, especially if we are in a difficult situation and I can't help, so how could I possibly deal with this? (I'm level 14 now, but I'll probably level up more before the BBEG).

Any tactics or new spell choices are also worth tips