You do not need to use MUI at all if you prefer to only export custom components. It is not a requirement of using Quest. We suggest it can help jump start your projects but it is not necessary and you can use your own design systems or components. This applies to customers starting from scratch or if they already have a React app that uses custom components made in house, or Ant or Chakra for example. Simply export any of your Figma designs into Quest without copying and pasting any MUI components into them.