Say you have a high-level wizard that can cast True Polymorph, and they turn into a Wight. They then use the Wight's Life Drain action, and manage to create a few zombies. Let's assume the Wizard does not maintain concentration for the full duration, so the True Polymorph is not permanent.
Do the zombies remain under the wizard's permanent control once the True Polymorph spell wears off (or is dispelled)?
I would prefer something concrete from the rules that would provide a definitive answer on this, but I also understand if it comes down to "DM's choice."
As a side note, this is for my very first campaign as a DM that will be starting up soonish, and the group I play with are very creative in their tomfoolery, so I am expecting one of them to try something along these lines.