The Plus/Delta technique is a way of capturing advice from team contributors while minimizing unproductive time spent complaining. First ask for positives: the things done right. Listen carefully to understand how to replicate the outcomes in the next project. Reflect on the success and briefly celebrate.
Move on to things team members would change if they had the project to do over. Focus on how to do it different. Gather ideas and suppress complaints. Listen to advice from all project stakeholders, then allow yourself time to craft a new way of leading the next project.
Wear your scars as a super power badge – giving you courage to lead the next project the way you know is right.