As @Grant has already mentioned there is no reason to enable the root user account. Only very old school *nix admins will insist on having a root user account these days since that is what they are familiar with, but there are multiple reasons to avoid having a root user account activated.
If you cannot perform some action using "sudo", then it either means you are trying to do something incorrectly or too complex for a single line. When this happens, you should consider other approaches to performing the action. In rare cases you may want to verify a complex command works as root since a complex command involving "sudo" can be difficult to create (usually best to create a small script at that point -- again another method not requiring a root user account), but you can easily get access to a root prompt without enabling a root user by using (there may be better options to include):
sudo su -
FYI, you need to use the admin account password for the admin user account you are currently using (not your AppleID password).
What is the exact command you are trying to run? The partial error message you provided seems like you may have used "su" instead of "sudo", but the error message you provided doesn't seem like it the exact complete error message.
Did you try using "sudo" from another admin user account like @Grant suggested? This will tell us whether the problem is system wide or just an issue with your main user account. Very important information.
Also, are you using any anti-virus software, cleaning apps, or third party security software? If so, then they might be the source of your problem since they interfere with the normal operation of macOS.
Is this Mac being managed by a school or business? If you purchased this Mac through a school or employer, it may have been configured from the factory to be managed by the school or business MDM even if it is your own personal Mac (another user recently discovered this on their brand new "personal" Mac). A managed Mac may be configured to prevent access to "sudo" even if you are an admin user. Technically it would be possible to configure "sudo" to block itself if you or some app customized the "sudoers" configuration.
Again, do not enable the root user account as there is no good reason for it which is why Apple has made it even more difficult to enable these days. Plus even being root won't allow you to access or modify certain parts of macOS or the file system due to the very increased security Apple has implemented within macOS. "sudo" should be able to do everything you need from root access.