Hello
Thank you for your question and reaching out. I can understand you are having query\issues related to Windows update reboot.
When you Click on Retry button it should ask again for Reboot.
On this Server > Open Task Scheduler > Task Scheduler Library > Microsoft > Windows > UpdateOrchestrator -> Right-click Reboot and choose Disable.
Then Enable it when you are ready to Reboot your Server.
https://learn.microsoft.com/en-us/windows/deployment/update/waas-restart
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