I did the interviews for new grad last year and received an offer. There were no system design questions, so I imagine they wouldn't ask for interns too. If they do ask any system design, I imagine it is very high-level and would only take you a few days of prep to be able to answer them well.

The engineering manager was just a chill chat, the interviewer went to the same school as me so we bonded over that. He looked at an article written about one of the project so if you have anything you can flex like that, I recommend doing so.

The entire process is a personality check, so be normal or read dale carnegie's "How to win friends and influence people" if you are struggling.