Which leadership theories if any could help new leader deal with this transition?

New leaders can benefit from transformational leadership theory, which emphasizes inspiring and motivating team members to embrace change and work towards a shared vision. Additionally, situational leadership theory can be valuable, as it encourages leaders to adapt their style based on the team's needs and the specific context of the transition. By combining these approaches, new leaders can foster collaboration, build trust, and effectively guide their teams through the challenges of transition.