I could not find a reliable per-user setting that works with just logoff/logon for Windows 11 like I found for Windows 10 in Disabling the Windows 10 and Windows 11 news (and weather) feeds.
So (for now?) there is only a global Globally which needs admin rights and a logoff/logon sequence:
:: requires admin
reg add "HKLM\Software\Policies\Microsoft\Dsh" /v "AllowNewsAndInterests" /t REG_DWORD /d "0" /f
echo logoff/logon to apply the change, or restart Explorer
Via:





