I would like to close my United mileage program account, but it seems not possible.

I know the miles never expire and most people don't care since it doesn't cost anything to leave it open. But I don't like to leave much of a digital trace or more than it is needed and I like to clean up after myself. There is no button to delete the account and all I found was an email and allegedly it is possible to deactivate the account but I would have to upload my ID somewhere which is something I'd hate to do.

Were you able to close and permanently delete an account with United? Or for that sake any other mileage account?