Hint: the reason why the structure of the EU was designed so that national parliaments would pass their own versions of laws agreed to in the EU parliament was precisely because it is the national laws that are binding. Similarly the EU courts rule on actions of the member states in the context of the EU, whether the member states are living up to their agreement. They do not directly rule on laws or override laws in the national parliaments.
Read these two pages. They are fairly clear, contain references to primary sources, and disagree with your claims:
https://ec.europa.eu/info/law/law-making-process/types-eu-la...
https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=LEGISSUM...
Article 288 Treaty on Functioning of the EU
(ex Article 249 TEC)
To exercise the Union's competences, the institutions shall adopt regulations, directives, decisions, recommendations and opinions.
A regulation shall have general application. It shall be binding in its entirety and directly applicable in all Member States. [...]
The grandparent is right and you're wrong.
Also, be very wary about quoting sources that end in a domain .EU, they're obviously biased.
17. Declaration concerning primacy
The Conference recalls that, in accordance with well settled case law of the Court of Justice of the European Union, the Treaties and the law adopted by the Union on the basis of the Treaties have primacy over the law of Member States, under the conditions laid down by the said case law.