You are doing something wrong. You do not have to provide any demo video when all done correctly. This is only needed when I think you want to publish official public app.
Also scopes screen - no idea how you managed to get them shown as not yet verified. Here how it should look (I have just tried now following the guide step by step)
I have to admit that Google admin console is not the easiest and clearest thing to use.
Maybe this variation of simplified guide will help you: