Hi, I am Dave, I will help you with this.
Microsoft have recently released the 24H2 update that supersedes the 23H2 update and they are slowly releasing that update around the world, that is most likely why the 23H2 update is no longer offered by Windows updates.
The most successful method to install version 24H2 is to use the Windows 11 ISO.
Please follow the steps, this is then not like re-installing Windows, it is just like an update and your personal files, settings and installed software will not be affected.
Click this link:
https://www.microsoft.com/en-us/software-downlo...
to download the Windows 11 ISO
When the ISO file completes downloading
Disconnect from the Internet
Disconnect all external devices with the exception of a mouse or keyboard.
Temporarily disable any 3rd party Anti-virus you may have installed
Then, in Windows File Explorer, double click the ISO and then run Setup.exe and select the Install option.