Bubble app names
App names are used for indexing purposes on Bubble's side, so they cannot be changed or reused once the app is created. Once you are on a custom domain, however, the app name is no longer visible to your end users.
If you are looking to change your app's name, you can create a copy of your existing app with the new app name that you prefer. However, if your app is currently on a paid plan or has any plugin licenses, please do keep in mind that those cannot be transferred to the new app.