Hi, François Chamberland.
Welcome to Microsoft support community.
We noticed you are having problem with account permission and how to migrate account profile.
Thanks for reaching us for your question.
As for the user permission it is actually more complex than admin user / standard user. To be honest as a community supporter I have not even grasp enough knowledge about it. I do not know what your permission issue really is since I am not the remote supporter at that time.
Unfortunately, because the complex nature of computer system there does not seem to be an automatic way to merge two accounts, so the best solution for us is probably trying to figure out what permission issue is.
If you have no idea what type of account is in your previous setting. We suggest:
Login to that account. Open Settings. Click Accounts. Click Your info. There should be a most basic indication about if you are running a admin account or not.
Otherwise, you could open start menu; search CMD; open it. Input command:
net user <your username>
There should be more detail information about the account info of that account(if you are using the admin account from Windows default setup there should be a Administrators group in account info).
Below is something I found with more complete view of user account. If you are interested, visit: Security identifiers | Microsoft Learn
Let me know your thoughts. Looking forward about your reply.
Best Regards
Benjamin.C- MSFT | Microsoft Community Support Specialist