The TL;DR is that Vuetify scaffolded the app to use file based routing and the ability to control layouts via the Component in route blocks like so:

<route lang="yaml">
meta:
  layout: 404
</route>

So for you to use your various layout components, you can define which component uses which layout via the above block inside the component. If nothing is specified, the default behavior is to use layouts/default.vue. you can read more at https://github.com/JohnCampionJr/vite-plugin-vue-layouts and see examples at https://github.com/antfu-collective/vitesse/tree/main/src. If interested, you can read about file-based routing implementation at https://vueschool.io/articles/vuejs-tutorials/automatic-file-based-routing-in-vue-js-with-typescript-support/ and https://github.com/posva/unplugin-vue-router