Earlier quoted context omitted.
> no longer countries Well, no. The entities united in the European Union are still Countries - Sovereign States, "governments over permanent populations in defined territories enabled to relate with peers, entering as part of the international community after recognition from at least one peer". They have embassies and deal with embassies. The distinction you are trying to convey, allegedly changing the scenario in…
EU law arguably has a greater weight than individual constitutions now. There are some countries like Poland which claim to not accept that, but the principle of EU law supremacy has become generally accepted (even without a referendum in that sense...)
The EU Council and the EU Commission can issue "Directives", which States must implement, and "Regulations", direct laws, with power to override national ones. (Plus "Decisions", "Recommendations" and "Opinions" - see https://european-union.europa.eu/institutions-law-budget/law... ) The possibility of "Regulations" is clearly and explicitly a delicate matter which has to find the right space for movement in a collection of Sovereign States.
Constitutions and laws are very different entities: a Constitution is the Social Contract to which citizens subscribe, the collection of the guidelines defining the National Project. This already entails, a Constitution indicates a Country - it strengthens the point.
This said, I am still confused about that original idea some proposed, according to which Countries and Not-Sovereign States have critical differences in energy trade.