Wait maybe another 30 minutes to test if the update completes.
If not, is the update stuck in the downloading phase inside Widows, or has your system rebooted and on a black screen installing the update?
1
If your PC has rebooted and stuck on a black screen installing the update, you have no other choice, press and hold the power button on the case of your PC to perform a hard shut down, wait a few seconds, then start your PC again, the update should then either complete or roll back.
2
If the update is stuck inside Windows in the download phase, please provide a screenshot of the updates window in the Settings app.