Disclaimer: In order not to cause harm to the client. I avoided sensible information in this debriefing, those information are only mine and may not reflect the client's view.
What was new to me was to meet the WCAG standards to create my interfaces. I browsed online and ask for help to my certified co-worker to learn more about it. It gave me the opportunity to grow and to change my vision about my work to include more users. I'll definitely use that on my next projects.
My second lesson was to discover new agile methods, such as PI planning. It helps me see clearly what I had to do in the next sprints. It was a good way to manage 30+ people on the project and give a clear vision to everyone.
From my viewpoint, integration was the major problem, there were no front-end developer meaning that the back-end developers had to do the front themselves, leading to a hazardous result.
Sketch: mockups.
Marvel: prototype and user tests.
Zeplin: front-end handover.
A journey in wireframe, others in UI; a UI kit; the user tests.