Leadership can be being a top performer in an activity, too. One of my kids was the scoring leader (by a lot) for her HS quiz bowl team. 3rd in state individually senior year, and led her team to their best finish ever. She also has convinced several friends to join the team over the years. But she wasn’t the team captain.
In robotics, she took the awards preparation role on as part of her responsibilities in her first year. Not a captain or team lead. But she wrote the applications that got her team a couple of really high level awards, and talked about that on her app. She had great admissions results, and even answers an essay question about leadership with examples like these.
Leadership isn’t titles. It is action, and top performance all the time even if no one is paying much attention. People eventually notice and follow competent people.