Based upon the supplied information, there are the following findings:
When you create a new macOS user profile, the password used to log into that Mac account is separate from the Apple Account credentials used for services such as iCloud. Apple Support — If you forgot your Mac login password
In your case, you report that you successfully signed in to your Apple Account and completed the verification process, but after reaching the desktop, System Settings appeared to show that you were not fully signed in and asked you to sign in again.
That is the specific behaviour that needs to be explained. It is not, by itself, explained simply by the fact that this is a newly created Mac user account.
It is also important to distinguish between a request for the Mac user account password and a request to sign in to the Apple Account. The information provided does not establish which credential macOS is requesting the second time.
The information provided does not establish why macOS is making the additional request, nor does it establish that a second Apple Account is involved.
The different profile pictures also do not, by themselves, establish that another account is being used.
The next step is therefore to identify exactly what macOS is requesting. Please provide the exact wording of the second sign-in request, or a screenshot with personal information covered. That will allow the cause to be assessed without assuming what the second request represents.
Apple's general information about signing in to an Apple Account on a Mac is available here: Apple Support — Set up your Mac
