I want to be able to create a user authentication system or something like that. If there are any alternatives please let me know!
I don't think there is, since most people seem to dismiss it as a dead language. Alternatives are either - learn a different backend language (e.g. if you know JS, you could learn how to use NodeJS, or you could learn Ruby or Go, or you could use Flask or Django with Python), download PHP, or see if you can find another online IDE that supports it.