Hello! I'm Jen, and I'd be happy to help you out with this issue.
I'm sorry to hear you're experiencing this issue. Please try manually starting the Windows Installer Service and check if it helps. Press Windows key + R to open the Run command window then type in services.msc and hit Enter. In the Services window, look for "Windows Installer" service, right-click on it and select Start. Run Windows update and see if the issue is fixed. If the problem persists, you can also try restarting "Windows Update" service in the Services window. Right-click on it and select Restart. Let me know if this works. Thank you.
I hope this information helps. If you have any questions, please let me know and I'll be glad to assist you further.
Best Regards!
Jen :)