I have worked as a full time Front-end engineer in AJA Creative, I had several large scale software and design development here, such as starlux-airlines.com, we built it with Vue.js and Nuxt.js, and I worked with a design team to make the whole website responsible, reusable and user friendly.
we've completed a website revision which is a responding to a telecom operator in Taiwan - fetnet.net(遠傳電信), the system behinds it is pretty complicated, we have to deal with CMS that suits module components that we designed, and built with React.js, the design team is composes of various UX and UI designers, the trickiest part is once we define the design guideline, everyone should follows it. Make sure the rules is can be followed and maintainable.