Sorry to hear that you are experiencing this issue. An unsuccessful update can remain pending and cause Windows to continue requesting a restart.
First, please go to Settings > Windows Update > Update history and check which update failed. Please share its name or KB number and the error code shown there.
In the meantime, run the Windows Update troubleshooter:
- Open Settings > System > Troubleshoot > Other troubleshooters.
- Find Windows Update and select Run.
- Apply any recommended fixes and restart the computer.