I told you that the 2nd Republic of Poland was formed in 1918.<quoted text>
Nooope. Poland and especially Prussia were Protestant. The Catholic Germans were in the south, Bavaria.
We are looking at pre-war, circa 1900:
Religion of Germany
That tan area on the map is the Protestant religion of Prussia & Poland.
She was a Polish citizen of the Catholic Polish 2nd republic.
Here is a map of Poland after 1918.