No, Poland is not a vassal. Hungary demonstrates it is quite possible to have a foreign policy that is literally hostile and still being part of the Union. At any time any country can leave the Union as UK demonstrated. So all member in the EU wants to be part of the union, they are not vassal. Poles do not want a communist government influenced by Russia. This is a fact. As of 2022, 97% of poles view Russia unfavorably and 89% view EU favorably. You cannot be more clear than that.