"...Trump has been rightly criticized for not affirming, during his previous European trip, American support for NATO's Article V..." Actually, that criticism wasn't "rightly" at all. Trump refused to affirm Article V in front of an audience of Germans, French and Dutch for a very good reason. First, all those countries refuse to meet the, rather minimal, 2% of GDP obligation; second, does anyone really, seriously expect the French or the Dutch, even the Germans, to honor Article V themselves if say Latvia or Poland were attacked? Of course not.
Trump waited for an audience of serious and reliable allies of America (yes, i know after years of communist deprivations their actual monetary commitment is small(ish), but it is reliable and does meet that commitment), to affirm Article V.
No, coming to a military aid of Poland without coming to the aid of Germany or France is not realistically possible; but Trump let it be known that if it was, that's exactly what he would do.