In Doctor Strange The Ancient One comments that she looks into the future.
The Ancient One: I've spent so many years peering through time, looking at this exact moment. But I can't see past it. I've prevented countless terrible futures and after each one there's always another, and they all lead here but never further.
Strange: You think this is where you die.
The Ancient One: You wonder what I see in your future?
Strange: No. Yes.
The Ancient One: I never saw your future, only its possibilities. You have such a capacity for goodness. You've always excelled, but not because you crave success but because of your fear of failure.
She was in possession of the Eye of Agamotto when Bruce goes to see her in Avengers: Endgame and is the top sorcerer at that point in time. It seems only logical she would be able to peer into the future.
As for why she didn’t? Well she seemed to be too busy questioning Hulk and not really believing his story to spend time looking into the future. It also looks like when looking into the future you would become quite vulnerable so maybe she didn’t want to do it if Hulk was a Bad Guy.