Modern observatories rely on wavefront sensing and control to achieve their ultimate angular resolution. Adaptive optics (AO) has become a cornerstone of large telescope instrumentation, and all ELT instruments will operate behind an AO system. While AO technologies are now highly mature, several challenges still require further development and on-sky validation, particularly for high-contrast imaging and the direct detection of exoplanets — the main focus of this talk. Progress in this field depends on extensive on-sky experimentation, yet access to large telescopes for instrumentation R&D remains limited. PAPYRUS was created to address this gap by transforming a small legacy telescope at Observatoire de Haute-Provence into a dedicated adaptive optics platform for on-sky technology maturation. Operating from June 2022 to April 2026, PAPYRUS has enabled the testing of innovative wavefront sensing and control concepts under real observing conditions while fostering collaborations across the community. In this presentation, I will review four years of activities on the platform, highlight key technical and scientific results, and discuss the lessons learned from operating a flexible on-sky testbed designed to prepare future AO strategies for the ELT era.