How was the responsibility hierarchy built in the team? Who was responsible for deadlines?

The vertical of responsibility in a team is usually built with the allocation of roles and zones of responsibility:

• The project manager or team lead is responsible for deadlines and coordinating the team's work.
• Developers are responsible for completing tasks within their competencies.
• QA is responsible for quality and testing.

In most cases, it is the team lead or project manager who is responsible for meeting deadlines, planning and distributing tasks, as well as communicating with the customer or stakeholders. This allows developers to focus on technical implementation, while management can monitor progress and risks.