So maybe your system Updater is not completely out … let’s concentrate on that.
It is the case that all the builds before early/mid October 2024 are missing or lost due to a server outage. Added to which there were build difficulties with dreamlte at about this time so even fewer builds are available.
You have a stable=official build, see Different Build Types.
Your upgrade path is that you have to do the transition from Android 11 (R) to Android 12 (S).
You can see the small number of builds available here /e/OS official dreamlte download.
An explanation and pictures of the system Updater set up for Android version upgrade is seen in this thread Update path for Galaxy S9.
Does your Updater show one “non-available” build only ? Are you able to scroll down the view to find an option marked (in blue) “version upgrade ?
If your Updater cannot do the above you should try
Settings > Apps and notifications > See all … apps > 3 dot menu top right > Show system > Updater > Storage & cache > Clear storage.
Perhaps restart the phone with a Soft reset Volume Down + Power at the same time, for 7 seconds.
… now be prepared to tap the refresh button multiple times, especially avoid times over the weekend where the network is busy.