I could be mistaken, but what you set up is an isolated network so SQL can talk to AWS for authentication using AD authentication BUT you have no computers joined to the AD domain. Is that correct?
If so, you will need to join a computer to the AWS AD domain and use that computer to authenticate to the SQL instance.
In order for you to do AD authentication, you have to have a trust between your workstation and the AD controller. Otherwise the AD controller has no idea who you are and your machine has no idea about the AD controller.
You would also need to create and grant an AD user access to the SQL instance.
The above is all just my opinion on what you should do.
As with all advice you find on a random internet forum - you shouldn't blindly follow it. Always test on a test server to see if there is negative side effects before making changes to live!
I recommend you NEVER run "random code" you found online on any system you care about UNLESS you understand and can verify the code OR you don't care if the code trashes your system.