Her designs — girlish, preppy and grungy at once — have proliferated on resale platforms like Depop and the RealReal. They have also been embraced by Generation Z celebrities like Olivia Rodrigo, Lola Tung and Addison Rae — none of whom were born when Ms. Sui first became a star in the New York fashion world and beyond. On Saturday, Ms. Sui will show her fall 2026 collection at New York Fashion Week.