Nvidia Preparation - I need help

I have on-campus placements season starting next sem, OAs will start around October and interviews for shortlisted candidates would be in December. I wanna prepare for systems software engineer role at Nvidia. What are all the major and minor things which I should focus on? Also, would an AI intern be relevant or of any use for this role, since I don't have any professional experience in systems software engineering, but in applications programming. I have good grasp of operating systems concepts.
Currently, I'm practicing problems on Leetcode and Codeforces, and regularly giving contests.
What are the things which I should be doing alongside? I have just one systems project, and that too in the userland. I need serious advice from experienced guys, who are already working in such roles, or preparing for such roles.
What all things should I study, and what project should I do?