Pulisic is really started to adapt well to his U.S. team. The adjustment period was rough, but he is a talented athlete who has so much potential. I think that the signs that he is meshing with his team will lead to an amazing upcoming season, and perhaps career highs, for him.
Yes, I believe Pulisic getting more comfortable with his squad is going to lead to breakout performances. When any team bonds and becomes more comfortable with one another, they are able to perform better. The trust they have built allows them to work better together, leading to an increase in performance for the entire team.
Yes, he will play better. He is now fast becoming a celebrity in the United States and has a fire in his belly that he did not seem to have before in his playing. He will be courted by sponsors galore so will have a concrete incentive to play his little heart out.
As someone who's worked as a sports reporter, I know that reporters are usually just looking to support some narrative that they have developed so that they can write a cohesive story on it. In this case, a reporter probably was hoping to write a story on Christian Pulisic "getting more comfortable" with Team USA, so he asked a slightly leading question about whether Pulisic was getting more comfortable. Of course Pulisic said yes; no one could ever say no to a question like that. So while it's certainly possible that Pulisic will have a breakout performance, his quote is probably meaningless.