Opinions [vary a bit](https://politics.stackexchange.com/questions/69329/how-does-the-polish-courts-rejection-of-eu-law-supremacy-differ-from-germanys) on interpreting the Polish court decision. 

But they haven't declared any parts of the treaties illegal *per se*. They've only declared some CJEU decisions illegal in Poland. Under the treaties, Poland signed up to the acquis, but those decisions were taken after Poland became a member, so they don't fall under the acquis... and arguably the decisions [were a little bit innovative](https://verfassungsblog.de/commission-v-poland-a-stepping-stone-towards-a-strong-union-of-values/) in their interpretation of treaty provisions. (Although the Polish court rejected wholesale the CJEU interpretation of Article 19(1)--it's at most [two decisions](https://journals.sagepub.com/doi/full/10.1177/1023263X19892185) that are involved both taken after 2018.) Several EU countries (including Germany, Denmark) reject total supremacy of EU law, to various extent[s]. See quotes in the previously linked Politics SE article.