How can I get rid of the “Some of these settings are managed by your organization” message?

Have you checked if there's a policy file on your PC? Sometimes, even after an update, certain settings can get stuck due to remnants of previous configurations. You can try running the Group Policy Editor command to see if that clears anything up. Just type 'gpedit.msc' in the Run dialog box. If that doesn't work, you might want to look at restoring your system settings to a previous state where everything functioned properly.

Did you install a cracked version of Windows? Sometimes those versions have hidden configurations that can trigger this kind of message. If that’s not the case, you could also try creating a new user account with administrative rights to check if the issue is specific to your current account.