How do I completely stop windows 11 to try to install on my windows 10 ?

Hello, thank you for reaching out to Microsoft Q&A.

To permanently block Windows 11 updates on your Windows 10 PC, follow these steps:

1. Click the Windows + R keys, type Regedit, and click OK.
2. Navigate to the following folder:

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate

3. In the right pane, double-click 'TargetReleaseVersion' registry key and change its value to 1.

Then, double-click the 'TargetReleaseVersionInfo' registry key, type 22H2, and click OK.

(If your Windows version is 21H2, replace the value data with 21H2).

4. Close the registry editor and restart your computer.

Disclaimer: Generally, modifying registry subkeys or work group is intended for advanced users, administrators, and IT Professionals. It can help fix some problems, however, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For further protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click How to back up and restore the registry in Windows - Microsoft Support to view the article.

https://support.microsoft.com/help/855140ad-e318-2a13-2829-d428a2ab0692

Let me know if you still need more help.