If you don't want to wait (for whatever reason it is not displaying), I posted a detailed walkthrough on page 3 of this thread.
I spent a lot of time myself trying to understand as it was there for weeks then disappeared when I had more time to do it, eventually I found those instructions on Lenovo forums.
I have done that walkthrough on my computer and my friends and I am confident it will work for you.
Just make sure to undo the change after you get it updated (you will understand when get to that point), or else when 24H2 comes eventually it will never find it.
23H2 didn't update as smooth as I hoped to be honest, I recommend preparing for a restore (just incase)
- I first updated in novemeber via Windows Update, had audio bug, so i downgraded until I had time at Christmas (need it for classes)
- Then update was missing by the time Christmas came, so I updated via the website tool, which locked me out of the App Store and some apps for some reason..
- had to get help from Microsoft and end result was System Restore (which will keep your personal files)
- but I thought, heck, I have the Factory files on USB and most of my stuff is in the cloud or a external SSD,, so I started fresh
- it still did not want to see 23H2 after the factory restore
- then did the method on page 3 to force it to find the update
- I am now on 23H2 and have updated it a couple times since, and have not noticed new bugs this time
Hopefully my experience helps.. reply back if not and I'll see if I know
Also, if you need Microsofts help ever, there is a chat you can do and they can take control of your PC to try and fix it while you watch them