Fitting in additional breakers is not usually a problem and adding an expansion panel isn't either. If the supply from the transformer isn't enough, then I don

Fitting in additional breakers is not usually a problem and adding an expansion panel isn't either. If the supply from the transformer isn't enough, then I don't see a regulation requiring a 220v in your garage affecting that. Whether it's new or an an upgrade later, you are going to have the same problem.