Account to create and publish 1 Android app for lifetime
Yes, you get the apk file of your app. You can upload it to Play Store, or to other Android stores.
No, this is no difficult. No technical skill is required.
No, there is no monthly fee, no yearly fee. You will have access for lifetime to the online app builder.
Yes, you publish the app under your own Google Developer Account. You get the APK file of the app, and you can publish on any Android store.