I want to up date to macOS Monterey 12. 2.1, failed "because not an owner"?

You have to be the administrator and in the administrator account. So, go to system preferences Users & Groups and make sure you are in the admin account. What is the exact message you recieve?If an error occurred while updating or installing macOS - Apple Support

You may need find out if your computer is authorized with your Apple ID.Authorize or deauthorize your computer for iTunes Store purchases - Apple Support Since Monterey comes from the App Store It checks your computer and if it's authorized. Are you the original owner?If another owner had this computer and failed to de-authorize it. That could be a problem. If not it's something else. You could try going to the App Store and under store in the top menu sign out if your signed in. restart computer and sign in again . Then try it.

I am the administrator. Still doesn't work.