@Tathagata Bhattacharya, Thanks for posting in Q&A. In Intune, we can configure Feature update policy and select a Windows 10 version that you want devices to remain at, Here is a link with more details for your reference:
https://learn.microsoft.com/en-us/mem/intune/protect/windows-10-feature-updates
The registry key TargetReleaseVersion under HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate to block windows 11 updates when user check for updates.
https://allthings.how/how-to-stop-windows-11-update-from-installing-on-your-windows-10-pc/
Note: Non-Microsoft link, just for the reference.
Hope the above information can help.
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