Poland is a NATO member, Ukraine is not, and Russia is very much aware of the difference that makes.
The Poles do not universally have a sense of brotherhood with the Ukrainians, especially now that they have hundreds of thousands of Ukrainian refugees in their country.
Poles have a sense of solidarity with Ukrainians. Especially since we helped their women and children.
The Ukrainians are fighting for their homes and loved ones.
Here is my prediction of what will happen when Ukraine wins this war and the fighting stops. Two important facts: Many Ukraine men have been killed and seriously wounded. There will be a tremendous building boom when peace returns. Here is one important way in which I expect these factors to influence the future of Polish/Ukraine relations.
There will be a significant number of Ukraine widows, and young girls becoming women soon. They will want husbands, and with a significant reduction in availability of suitable husband material among Ukrainian men, they will end up marrying a Pole, or a German, or even an emmigrated Russian (one who refused to fight for Putin). With the building boom in Ukraine there will be many well paid jobs and opportunities for starting small and larger businesses. I suspect Ukrainian wifes will be encouraging their foreign born husbands to move to Ukraine to improve the family fortunes. This is especially likely if the wife still has some family living in Ukraine to provide emotional and temporary housing support. These women will have children, and especially if there are other Ukrainian relatives, the Ukrainian language will be the language most learned, although the father’s language will also be part of their lives. In fact I suspect many Ukrainian children will grow up multilingual—mother’s tongue, father’s language, and Russian.
The children will tend to consider themselves Ukrainian rather than Polish, etc. Thus Ukraine despite this deadly war, will survive the terrible sacrifice of their young men, as Ukraine born wives save the heart of the nation.
With both their parents from East Prussia, I remember how my mother and her sisters visited Europe a number of times when boat passage was cheap during the Depression. One sister even married over there and was stuck in Europe for the entire WW2. My vivid memories of my mother and her siblings worrying about family and her sister in Europe influence my current concern and interest in this Russia/Ukraine war. I remember even better helping my mother prepare Red Cross packages to send to family over there during the difficult reconstruction period. My mother and siblings clearly felt themselves to be American because this is where they grew up. Their parents insisted on everyong speaking English, and the only one who learned his parents original language really well was cared for by his mother’s sister for 2 months of quarantined illness as a young child.