We were talking about this today, and sometime soon I will write an article to explain the pros and cons of the different ways of signing in. It would not surprise me if Google add a similar feature to Apple’s at some point. Then I’ll have to update the article.
In your case, when you first used Apple ID to sign in you chose to Hide My Email. That is in theory a good idea. People like us only see an address that looks like email@example.com, so we don’t know what your original Apple ID is. When we send an email to you, Apple checks to see if the message came from us in particular, and if it did, the message is forwarded to your real Apple ID email address. If you look at the Reply To for any such email, you will see that it includes the obfuscation address too.
I am able to see that under your hide email address you do have one model that you were working on. You ought to be able to sign in with Apple, using your real Apple ID, to here: app.sketchup.com/app
and see that model in the Trimble Connect part of the page. If after having used the Free version you realized that hiding your email wasn’t ideal, and changed your Apple ID settings to use your real email address when signing into SketchUp, then that one model will not be connected to your account.
I am able to move the model over to the account you want it to be in. Could you try using sign in with Apple on this page:
and use the Customer Service, Message Us option, to give me the details of which account the model is in now, and which one you would like it to be in. Make sure to mention my name, so that my colleagues will send the request to me.