The plan has always been that once Avatar 2 hit screens, the additional sequels would follow in the same release window every year until they’re done.
The movie has had so many release dates over such a long period of time that if Avatar 2 had made its initial schedule we’d be getting ready for Avatar 3 or Avatar 4 at this point.
Originally James Cameron said he’s be shooting all sequels at once, so it’s possible that’s what Saldana is gearing up for.
Zoe Saldana doesn’t mention them so it’s not clear if, once filming begins they’ll be shooting for one more than one movie or coming back later to do Avatar 3.