Recent circumstances (e.g., COVID-19, socio-political tensions) exacerbate persistent teacher shortages, reinforcing the need to attend to factors associated with teacher retention. In this multimethod study, we explore outcomes of an online, year-long professional development focused on collaboration and autonomy -- two factors correlated with teacher retention. The professional development exposed educators to deeper learning and personalized learning approaches, and sought to transform collaborative practices. Findings reveal that teachers' practices expanded and beliefs became more positive over time. Further, teachers believe they must forego prior expectations for teaching and learning through mind-set changes that strengthen collaboration and embrace new pedagogical approaches.