[Vuejs]-Restoring Vue state (vuex) when reopening app

There should be two ways to solve your problem:

• You can use a plugin (for example @capacitor-firebase/authentication). This persists the state for you and fires onAuthStateChanged on startup.
• You can try to set persistence to indexedDBLocalPersistence when initializing Firebase Authentication:

initializeAuth(firebaseApp, {
  persistence: indexedDBLocalPersistence
});