Hi This was a common problem
Windows 11 needs to Run As Administrator to install UEFN updates
Works fine on Windows 10, but Windows 11 Enhanced Security needs “Run As Administrator”
There may problem may be running Opera.
Try Microsoft Edge and Google Chrome to initially login and join you Epic account with Fortnite and installation then you can go back to Opera but we have seen problems where VPN had to be used with browser other than Chrome and derivatives.