I use the fuel injector cleaner as it comes on a 2 pack and is readily available. Mostly they all do the same thing I think.
The liquimoly video shows that the injector cleaner cleans the injectors as well as the cylinder walls and piston head. The full on fuel system.
They also have fuel system cleaner etc but I think they all do the same thing more or less. I think Chris fix also did a video on it and he used the STP injector cleaner.
Do share your findings as I think Kia manual specifically says not to use mmt fuel but use fuel with detergents. Now we only have detergents in hi octane fuel in Pakistan and our regular has lots of mmt and no detergents.