Windows server 2022 is not updating with latest patch KB5126655

Four months without a successful cumulative update, and a clean rollback when you install manually, usually points to component store trouble or a failed prerequisite, not to this specific KB. The rollback leaves a trail, so I would start there:

• Get the actual error code. In Event Viewer, look at Windows Logs > Setup and System around the install time, or run Get-WindowsUpdateLog. Codes like 0x800f0922, 0x800f0831 or 0x80073712 each point to a different fix, so the code matters more than the KB number.
• Check the CBS log at C:\Windows\Logs\CBS\CBS.log and search for the last Error lines before the rollback. They name the package or file that failed.
• Repair the component store: DISM /Online /Cleanup-Image /RestoreHealth, then sfc /scannow, then reboot and retry. If DISM cannot get its source files, point it at a Server 2022 ISO with /Source and /LimitAccess.
• Free space and pending work. Make sure the system drive has several GB free, no pending reboot is stuck (check for a pending.xml in C:\Windows\WinSxS), and the servicing stack update from your June baseline is installed.
• If it still rolls back, install the missing months in order (the latest Servicing Stack Update first, then the latest cumulative update) from the Microsoft Update Catalog, since an in-place repair needs a clean chain.

If you post the error code and the last few CBS.log errors, people here can narrow it down much faster.