Agreed. A wrongful termination means that you were terminated in violation of a specific law which prohibits your being fired for the reason the employer did.

It is the opt of the employer to demote you, with or without reason, with or without "representation" from HR (or anyone else) unless you have a legally binding contract that specifically says otherwise.

It is legal to terminate you because you left 15 minutes early without permission, no matter how badly you were feeling over what happened.

It is legal to terminate you as part of a downsizing of 20 additional people.

You will almost certainly qualify for unemployment; however, nothing you have posted gives you anything remotely close to a lawsuit.