Owner or Accountable?
Design is a process that typically involves a team. This is valuable and improves the design. Then, ego gets in the way. In this situation, focus on accountability and deny ownership.
Ownership makes designers afraid of others doing it wrong and puts the pressure on one individual. It turns good designers into bad bullies. Accountability makes designers clearly responsible for delivering a part of the product. Accountability allows a designer to focus on their strengths.
Summary: When you’re ready for production, focus on what each team member is accountable for. Accountability allows each designer to focus on their strength.