Hello Pronice.
Thank you for updating me that information. I'm sorry it didn't resolve the issue with RuntimeBroker.exe.
Please try this.
Login on the new local administrator account
Open File explorer then Under View > Show hidden items
Navigate to this folder
C:\Users<username of the main account>\AppData\Local\Packages\Microsoft.Windows.Cortana_cw5n1h2txyewy\Settings
Delete all the files there.
After that, Restart your PC then login on your main account.
If it doesn't work, Yes you can transfer all your files from your Old user account to the new one.
Login on the new local administrator account
Navigate to this path
C:\Users<username of the main account>\
Copy all the important files you will see in Desktop, Documents, Pictures folder etc. to the new user account.
Sincerely
John DeV
Independent Advisor