main.js

import { provide, createApp, h } from 'vue'
import { ApolloClients } from '@vue/apollo-composable'
import { UseApolloClients } from './src/util/useApolloClients.js'

import App from './App.vue'

// keep your URLs as env variables for easy dev/prod switching
const {
  VITE_GQL_URL_1: URL1,
  VITE_GQL_URL_2: URL2
} = import.meta.env

const app = createApp({
  name: 'MyApp',
  setup() {
    provide(ApolloClients, UseApolloClients(URL1, URL2))
  },
  render: () => h(App),
})

// other packages you might use...
// app.use(router)
// app.use(createPinia())

app.mount('#app')